diff --git a/config/docbook.m4 b/config/docbook.m4
index c485eaf737..f9307f329e 100644
--- a/config/docbook.m4
+++ b/config/docbook.m4
@@ -3,7 +3,7 @@
 # PGAC_PROG_NSGMLS
 # ----------------
 AC_DEFUN([PGAC_PROG_NSGMLS],
-[AC_PATH_PROGS([NSGMLS], [onsgmls nsgmls])])
+[PGAC_PATH_PROGS(NSGMLS, [onsgmls nsgmls])])
 
 
 # PGAC_CHECK_DOCBOOK(VERSION)
diff --git a/config/perl.m4 b/config/perl.m4
index 9706c4de6a..e44ca94313 100644
--- a/config/perl.m4
+++ b/config/perl.m4
@@ -4,10 +4,7 @@
 # PGAC_PATH_PERL
 # --------------
 AC_DEFUN([PGAC_PATH_PERL],
-[# Let the user override the search
-if test -z "$PERL"; then
-  AC_PATH_PROG(PERL, perl)
-fi
+[PGAC_PATH_PROGS(PERL, perl)
 
 if test "$PERL"; then
   pgac_perl_version=`$PERL -v 2>/dev/null | sed -n ['s/This is perl.*v[a-z ]*\([0-9]\.[0-9][0-9.]*\).*$/\1/p']`
diff --git a/config/programs.m4 b/config/programs.m4
index b7deb86a5f..aa84bfdb9e 100644
--- a/config/programs.m4
+++ b/config/programs.m4
@@ -1,6 +1,24 @@
 # config/programs.m4
 
 
+# PGAC_PATH_PROGS
+# ---------------
+# This wrapper for AC_PATH_PROGS behaves like that macro except when
+# VARIABLE is already set; in that case we just accept the value verbatim.
+# (AC_PATH_PROGS would accept it only if it looks like an absolute path.)
+# A desirable future improvement would be to convert a non-absolute-path
+# input into absolute form.
+AC_DEFUN([PGAC_PATH_PROGS],
+[if test -z "$$1"; then
+  AC_PATH_PROGS($@)
+else
+  # Report the value of $1 in configure's output in all cases.
+  AC_MSG_CHECKING([for $1])
+  AC_MSG_RESULT([$$1])
+fi
+])
+
+
 # PGAC_PATH_BISON
 # ---------------
 # Look for Bison, set the output variable BISON to its path if found.
@@ -8,10 +26,7 @@
 # Note we do not accept other implementations of yacc.
 
 AC_DEFUN([PGAC_PATH_BISON],
-[# Let the user override the search
-if test -z "$BISON"; then
-  AC_PATH_PROGS(BISON, bison)
-fi
+[PGAC_PATH_PROGS(BISON, bison)
 
 if test "$BISON"; then
   pgac_bison_version=`$BISON --version 2>/dev/null | sed q`
@@ -41,7 +56,7 @@ if test -z "$BISON"; then
 *** PostgreSQL then you do not need to worry about this, because the Bison
 *** output is pre-generated.)])
 fi
-# We don't need AC_SUBST(BISON) because AC_PATH_PROG did it
+# We don't need AC_SUBST(BISON) because PGAC_PATH_PROGS did it
 AC_SUBST(BISONFLAGS)
 ])# PGAC_PATH_BISON
 
@@ -229,7 +244,7 @@ AC_DEFUN([PGAC_CHECK_GETTEXT],
                  [AC_MSG_ERROR([a gettext implementation is required for NLS])])
   AC_CHECK_HEADER([libintl.h], [],
                   [AC_MSG_ERROR([header file <libintl.h> is required for NLS])])
-  AC_PATH_PROGS(MSGFMT, msgfmt)
+  PGAC_PATH_PROGS(MSGFMT, msgfmt)
   if test -z "$MSGFMT"; then
     AC_MSG_ERROR([msgfmt is required for NLS])
   fi
@@ -238,8 +253,8 @@ AC_DEFUN([PGAC_CHECK_GETTEXT],
     pgac_cv_msgfmt_flags=-c
 fi])
   AC_SUBST(MSGFMT_FLAGS, $pgac_cv_msgfmt_flags)
-  AC_PATH_PROGS(MSGMERGE, msgmerge)
-  AC_PATH_PROGS(XGETTEXT, xgettext)
+  PGAC_PATH_PROGS(MSGMERGE, msgmerge)
+  PGAC_PATH_PROGS(XGETTEXT, xgettext)
 ])# PGAC_CHECK_GETTEXT
 
 
diff --git a/config/python.m4 b/config/python.m4
index 953d709305..f3c7642229 100644
--- a/config/python.m4
+++ b/config/python.m4
@@ -6,10 +6,10 @@
 
 # PGAC_PATH_PYTHON
 # ----------------
-# Look for Python and set the output variable 'PYTHON'
-# to 'python' if found, empty otherwise.
+# Look for Python and set the output variable 'PYTHON' if found,
+# fail otherwise.
 AC_DEFUN([PGAC_PATH_PYTHON],
-[AC_PATH_PROG(PYTHON, python)
+[PGAC_PATH_PROGS(PYTHON, python)
 if test x"$PYTHON" = x""; then
   AC_MSG_ERROR([Python not found])
 fi
diff --git a/config/tcl.m4 b/config/tcl.m4
index 907deb9aa1..a4bf231947 100644
--- a/config/tcl.m4
+++ b/config/tcl.m4
@@ -4,7 +4,7 @@
 
 
 AC_DEFUN([PGAC_PATH_TCLSH],
-[AC_PATH_PROGS(TCLSH, [tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84])
+[PGAC_PATH_PROGS(TCLSH, [tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84])
 if test x"$TCLSH" = x""; then
   AC_MSG_ERROR([Tcl shell not found])
 fi
diff --git a/configure b/configure
index aeee815ced..8b24bf1128 100755
--- a/configure
+++ b/configure
@@ -3298,7 +3298,8 @@ if test "${enable_coverage+set}" = set; then :
   enableval=$enable_coverage;
   case $enableval in
     yes)
-      for ac_prog in gcov
+      if test -z "$GCOV"; then
+  for ac_prog in gcov
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -3343,10 +3344,19 @@ fi
   test -n "$GCOV" && break
 done
 
+else
+  # Report the value of GCOV in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for GCOV" >&5
+$as_echo_n "checking for GCOV... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $GCOV" >&5
+$as_echo "$GCOV" >&6; }
+fi
+
 if test -z "$GCOV"; then
   as_fn_error $? "gcov not found" "$LINENO" 5
 fi
-for ac_prog in lcov
+if test -z "$LCOV"; then
+  for ac_prog in lcov
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -3391,10 +3401,19 @@ fi
   test -n "$LCOV" && break
 done
 
+else
+  # Report the value of LCOV in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for LCOV" >&5
+$as_echo_n "checking for LCOV... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $LCOV" >&5
+$as_echo "$LCOV" >&6; }
+fi
+
 if test -z "$LCOV"; then
   as_fn_error $? "lcov not found" "$LINENO" 5
 fi
-for ac_prog in genhtml
+if test -z "$GENHTML"; then
+  for ac_prog in genhtml
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -3439,6 +3458,14 @@ fi
   test -n "$GENHTML" && break
 done
 
+else
+  # Report the value of GENHTML in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for GENHTML" >&5
+$as_echo_n "checking for GENHTML... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $GENHTML" >&5
+$as_echo "$GENHTML" >&6; }
+fi
+
 if test -z "$GENHTML"; then
   as_fn_error $? "genhtml not found" "$LINENO" 5
 fi
@@ -3469,7 +3496,8 @@ if test "${enable_dtrace+set}" = set; then :
   enableval=$enable_dtrace;
   case $enableval in
     yes)
-      for ac_prog in dtrace
+      if test -z "$DTRACE"; then
+  for ac_prog in dtrace
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -3514,6 +3542,14 @@ fi
   test -n "$DTRACE" && break
 done
 
+else
+  # Report the value of DTRACE in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for DTRACE" >&5
+$as_echo_n "checking for DTRACE... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DTRACE" >&5
+$as_echo "$DTRACE" >&6; }
+fi
+
 if test -z "$DTRACE"; then
   as_fn_error $? "dtrace not found" "$LINENO" 5
 fi
@@ -6266,6 +6302,7 @@ fi
 
 
 if test "$with_libxml" = yes ; then
+  if test -z "$XML2_CONFIG"; then
   for ac_prog in xml2-config
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -6311,6 +6348,14 @@ fi
   test -n "$XML2_CONFIG" && break
 done
 
+else
+  # Report the value of XML2_CONFIG in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for XML2_CONFIG" >&5
+$as_echo_n "checking for XML2_CONFIG... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $XML2_CONFIG" >&5
+$as_echo "$XML2_CONFIG" >&6; }
+fi
+
   if test -n "$XML2_CONFIG"; then
     for pgac_option in `$XML2_CONFIG --cflags`; do
       case $pgac_option in
@@ -7374,8 +7419,11 @@ case $INSTALL in
 esac
 
 
-# Extract the first word of "tar", so it can be a program name with args.
-set dummy tar; ac_word=$2
+if test -z "$TAR"; then
+  for ac_prog in tar
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
 if ${ac_cv_path_TAR+:} false; then :
@@ -7414,6 +7462,17 @@ $as_echo "no" >&6; }
 fi
 
 
+  test -n "$TAR" && break
+done
+
+else
+  # Report the value of TAR in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for TAR" >&5
+$as_echo_n "checking for TAR... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $TAR" >&5
+$as_echo "$TAR" >&6; }
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether ln -s works" >&5
 $as_echo_n "checking whether ln -s works... " >&6; }
 LN_S=$as_ln_s
@@ -7516,7 +7575,6 @@ case $MKDIR_P in
   *install-sh*) MKDIR_P='\${SHELL} \${top_srcdir}/config/install-sh -c -d';;
 esac
 
-# Let the user override the search
 if test -z "$BISON"; then
   for ac_prog in bison
 do
@@ -7563,8 +7621,15 @@ fi
   test -n "$BISON" && break
 done
 
+else
+  # Report the value of BISON in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for BISON" >&5
+$as_echo_n "checking for BISON... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $BISON" >&5
+$as_echo "$BISON" >&6; }
 fi
 
+
 if test "$BISON"; then
   pgac_bison_version=`$BISON --version 2>/dev/null | sed q`
   { $as_echo "$as_me:${as_lineno-$LINENO}: using $pgac_bison_version" >&5
@@ -7603,7 +7668,7 @@ $as_echo "$as_me: WARNING:
 *** PostgreSQL then you do not need to worry about this, because the Bison
 *** output is pre-generated.)" >&2;}
 fi
-# We don't need AC_SUBST(BISON) because AC_PATH_PROG did it
+# We don't need AC_SUBST(BISON) because PGAC_PATH_PROGS did it
 
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for flex" >&5
@@ -7679,10 +7744,11 @@ fi
 
 
 
-# Let the user override the search
 if test -z "$PERL"; then
-  # Extract the first word of "perl", so it can be a program name with args.
-set dummy perl; ac_word=$2
+  for ac_prog in perl
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
 if ${ac_cv_path_PERL+:} false; then :
@@ -7721,8 +7787,18 @@ $as_echo "no" >&6; }
 fi
 
 
+  test -n "$PERL" && break
+done
+
+else
+  # Report the value of PERL in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PERL" >&5
+$as_echo_n "checking for PERL... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PERL" >&5
+$as_echo "$PERL" >&6; }
 fi
 
+
 if test "$PERL"; then
   pgac_perl_version=`$PERL -v 2>/dev/null | sed -n 's/This is perl.*v[a-z ]*\([0-9]\.[0-9][0-9.]*\).*$/\1/p'`
   { $as_echo "$as_me:${as_lineno-$LINENO}: using perl $pgac_perl_version" >&5
@@ -7819,8 +7895,11 @@ fi
 fi
 
 if test "$with_python" = yes; then
-  # Extract the first word of "python", so it can be a program name with args.
-set dummy python; ac_word=$2
+  if test -z "$PYTHON"; then
+  for ac_prog in python
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
 if ${ac_cv_path_PYTHON+:} false; then :
@@ -7859,6 +7938,17 @@ $as_echo "no" >&6; }
 fi
 
 
+  test -n "$PYTHON" && break
+done
+
+else
+  # Report the value of PYTHON in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PYTHON" >&5
+$as_echo_n "checking for PYTHON... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PYTHON" >&5
+$as_echo "$PYTHON" >&6; }
+fi
+
 if test x"$PYTHON" = x""; then
   as_fn_error $? "Python not found" "$LINENO" 5
 fi
@@ -7997,8 +8087,11 @@ $as_echo "${python_libspec} ${python_additional_libs}" >&6; }
 fi
 
 if test "$cross_compiling" = yes && test -z "$with_system_tzdata"; then
-  # Extract the first word of "zic", so it can be a program name with args.
-set dummy zic; ac_word=$2
+  if test -z "$ZIC"; then
+  for ac_prog in zic
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
 if ${ac_cv_path_ZIC+:} false; then :
@@ -8037,6 +8130,17 @@ $as_echo "no" >&6; }
 fi
 
 
+  test -n "$ZIC" && break
+done
+
+else
+  # Report the value of ZIC in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ZIC" >&5
+$as_echo_n "checking for ZIC... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ZIC" >&5
+$as_echo "$ZIC" >&6; }
+fi
+
   if test -z "$ZIC"; then
     as_fn_error $? "
 When cross-compiling, either use the option --with-system-tzdata to use
@@ -15614,6 +15718,7 @@ else
 fi
 
 
+  if test -z "$MSGFMT"; then
   for ac_prog in msgfmt
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -15659,6 +15764,14 @@ fi
   test -n "$MSGFMT" && break
 done
 
+else
+  # Report the value of MSGFMT in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for MSGFMT" >&5
+$as_echo_n "checking for MSGFMT... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MSGFMT" >&5
+$as_echo "$MSGFMT" >&6; }
+fi
+
   if test -z "$MSGFMT"; then
     as_fn_error $? "msgfmt is required for NLS" "$LINENO" 5
   fi
@@ -15675,6 +15788,7 @@ fi
 $as_echo "$pgac_cv_msgfmt_flags" >&6; }
   MSGFMT_FLAGS=$pgac_cv_msgfmt_flags
 
+  if test -z "$MSGMERGE"; then
   for ac_prog in msgmerge
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -15720,6 +15834,15 @@ fi
   test -n "$MSGMERGE" && break
 done
 
+else
+  # Report the value of MSGMERGE in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for MSGMERGE" >&5
+$as_echo_n "checking for MSGMERGE... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $MSGMERGE" >&5
+$as_echo "$MSGMERGE" >&6; }
+fi
+
+  if test -z "$XGETTEXT"; then
   for ac_prog in xgettext
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -15765,12 +15888,21 @@ fi
   test -n "$XGETTEXT" && break
 done
 
+else
+  # Report the value of XGETTEXT in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for XGETTEXT" >&5
+$as_echo_n "checking for XGETTEXT... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $XGETTEXT" >&5
+$as_echo "$XGETTEXT" >&6; }
+fi
+
 
 fi
 
 # Check for Tcl configuration script tclConfig.sh
 if test "$with_tcl" = yes; then
-    for ac_prog in tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84
+    if test -z "$TCLSH"; then
+  for ac_prog in tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -15815,6 +15947,14 @@ fi
   test -n "$TCLSH" && break
 done
 
+else
+  # Report the value of TCLSH in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for TCLSH" >&5
+$as_echo_n "checking for TCLSH... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $TCLSH" >&5
+$as_echo "$TCLSH" >&6; }
+fi
+
 if test x"$TCLSH" = x""; then
   as_fn_error $? "Tcl shell not found" "$LINENO" 5
 fi
@@ -15941,7 +16081,8 @@ fi
 #
 # Check for DocBook and tools
 #
-for ac_prog in onsgmls nsgmls
+if test -z "$NSGMLS"; then
+  for ac_prog in onsgmls nsgmls
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -15986,6 +16127,14 @@ fi
   test -n "$NSGMLS" && break
 done
 
+else
+  # Report the value of NSGMLS in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for NSGMLS" >&5
+$as_echo_n "checking for NSGMLS... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $NSGMLS" >&5
+$as_echo "$NSGMLS" >&6; }
+fi
+
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for DocBook V4.2" >&5
 $as_echo_n "checking for DocBook V4.2... " >&6; }
@@ -16022,7 +16171,8 @@ $as_echo "$pgac_cv_check_docbook" >&6; }
 have_docbook=$pgac_cv_check_docbook
 
 
-for ac_prog in dbtoepub
+if test -z "$DBTOEPUB"; then
+  for ac_prog in dbtoepub
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -16067,7 +16217,16 @@ fi
   test -n "$DBTOEPUB" && break
 done
 
-for ac_prog in xmllint
+else
+  # Report the value of DBTOEPUB in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for DBTOEPUB" >&5
+$as_echo_n "checking for DBTOEPUB... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $DBTOEPUB" >&5
+$as_echo "$DBTOEPUB" >&6; }
+fi
+
+if test -z "$XMLLINT"; then
+  for ac_prog in xmllint
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -16112,7 +16271,16 @@ fi
   test -n "$XMLLINT" && break
 done
 
-for ac_prog in xsltproc
+else
+  # Report the value of XMLLINT in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for XMLLINT" >&5
+$as_echo_n "checking for XMLLINT... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $XMLLINT" >&5
+$as_echo "$XMLLINT" >&6; }
+fi
+
+if test -z "$XSLTPROC"; then
+  for ac_prog in xsltproc
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -16157,7 +16325,16 @@ fi
   test -n "$XSLTPROC" && break
 done
 
-for ac_prog in osx sgml2xml sx
+else
+  # Report the value of XSLTPROC in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for XSLTPROC" >&5
+$as_echo_n "checking for XSLTPROC... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $XSLTPROC" >&5
+$as_echo "$XSLTPROC" >&6; }
+fi
+
+if test -z "$OSX"; then
+  for ac_prog in osx sgml2xml sx
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -16202,7 +16379,16 @@ fi
   test -n "$OSX" && break
 done
 
-for ac_prog in fop
+else
+  # Report the value of OSX in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for OSX" >&5
+$as_echo_n "checking for OSX... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $OSX" >&5
+$as_echo "$OSX" >&6; }
+fi
+
+if test -z "$FOP"; then
+  for ac_prog in fop
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
 set dummy $ac_prog; ac_word=$2
@@ -16247,11 +16433,20 @@ fi
   test -n "$FOP" && break
 done
 
+else
+  # Report the value of FOP in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for FOP" >&5
+$as_echo_n "checking for FOP... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $FOP" >&5
+$as_echo "$FOP" >&6; }
+fi
+
 
 #
 # Check for test tools
 #
 if test "$enable_tap_tests" = yes; then
+  if test -z "$PROVE"; then
   for ac_prog in prove
 do
   # Extract the first word of "$ac_prog", so it can be a program name with args.
@@ -16297,6 +16492,14 @@ fi
   test -n "$PROVE" && break
 done
 
+else
+  # Report the value of PROVE in configure's output in all cases.
+  { $as_echo "$as_me:${as_lineno-$LINENO}: checking for PROVE" >&5
+$as_echo_n "checking for PROVE... " >&6; }
+  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $PROVE" >&5
+$as_echo "$PROVE" >&6; }
+fi
+
   if test -z "$PROVE"; then
     as_fn_error $? "prove not found" "$LINENO" 5
   fi
diff --git a/configure.in b/configure.in
index abfc7b524a..a0f0f85add 100644
--- a/configure.in
+++ b/configure.in
@@ -218,15 +218,15 @@ PGAC_ARG_BOOL(enable, profiling, no,
 #
 PGAC_ARG_BOOL(enable, coverage, no,
               [build with coverage testing instrumentation],
-[AC_PATH_PROGS(GCOV, gcov)
+[PGAC_PATH_PROGS(GCOV, gcov)
 if test -z "$GCOV"; then
   AC_MSG_ERROR([gcov not found])
 fi
-AC_PATH_PROGS(LCOV, lcov)
+PGAC_PATH_PROGS(LCOV, lcov)
 if test -z "$LCOV"; then
   AC_MSG_ERROR([lcov not found])
 fi
-AC_PATH_PROGS(GENHTML, genhtml)
+PGAC_PATH_PROGS(GENHTML, genhtml)
 if test -z "$GENHTML"; then
   AC_MSG_ERROR([genhtml not found])
 fi])
@@ -237,7 +237,7 @@ AC_SUBST(enable_coverage)
 #
 PGAC_ARG_BOOL(enable, dtrace, no,
               [build with DTrace support],
-[AC_PATH_PROGS(DTRACE, dtrace)
+[PGAC_PATH_PROGS(DTRACE, dtrace)
 if test -z "$DTRACE"; then
   AC_MSG_ERROR([dtrace not found])
 fi
@@ -816,7 +816,7 @@ PGAC_ARG_BOOL(with, libxml, no, [build with XML support],
               [AC_DEFINE([USE_LIBXML], 1, [Define to 1 to build with XML support. (--with-libxml)])])
 
 if test "$with_libxml" = yes ; then
-  AC_PATH_PROGS(XML2_CONFIG, xml2-config)
+  PGAC_PATH_PROGS(XML2_CONFIG, xml2-config)
   if test -n "$XML2_CONFIG"; then
     for pgac_option in `$XML2_CONFIG --cflags`; do
       case $pgac_option in
@@ -912,7 +912,7 @@ case $INSTALL in
 esac
 AC_SUBST(install_bin)
 
-AC_PATH_PROG(TAR, tar)
+PGAC_PATH_PROGS(TAR, tar)
 AC_PROG_LN_S
 AC_PROG_AWK
 AC_PROG_MKDIR_P
@@ -948,7 +948,7 @@ if test "$with_python" = yes; then
 fi
 
 if test "$cross_compiling" = yes && test -z "$with_system_tzdata"; then
-  AC_PATH_PROG(ZIC, zic)
+  PGAC_PATH_PROGS(ZIC, zic)
   if test -z "$ZIC"; then
     AC_MSG_ERROR([
 When cross-compiling, either use the option --with-system-tzdata to use
@@ -2119,17 +2119,17 @@ fi
 #
 PGAC_PROG_NSGMLS
 PGAC_CHECK_DOCBOOK(4.2)
-AC_PATH_PROGS(DBTOEPUB, dbtoepub)
-AC_PATH_PROGS(XMLLINT, xmllint)
-AC_PATH_PROGS(XSLTPROC, xsltproc)
-AC_PATH_PROGS(OSX, [osx sgml2xml sx])
-AC_PATH_PROGS(FOP, fop)
+PGAC_PATH_PROGS(DBTOEPUB, dbtoepub)
+PGAC_PATH_PROGS(XMLLINT, xmllint)
+PGAC_PATH_PROGS(XSLTPROC, xsltproc)
+PGAC_PATH_PROGS(OSX, [osx sgml2xml sx])
+PGAC_PATH_PROGS(FOP, fop)
 
 #
 # Check for test tools
 #
 if test "$enable_tap_tests" = yes; then
-  AC_PATH_PROGS(PROVE, prove)
+  PGAC_PATH_PROGS(PROVE, prove)
   if test -z "$PROVE"; then
     AC_MSG_ERROR([prove not found])
   fi