diff --git a/contrib/oid2name/oid2name.c b/contrib/oid2name/oid2name.c
index 17d4d80fc9..a666731e72 100644
--- a/contrib/oid2name/oid2name.c
+++ b/contrib/oid2name/oid2name.c
@@ -51,6 +51,7 @@ struct options
 static void help(const char *progname);
 void		get_opts(int, char **, struct options *);
 void	   *pg_malloc(size_t size);
+void	   *pg_realloc(void *ptr, size_t size);
 char	   *pg_strdup(const char *str);
 void		add_one_elt(char *eltname, eary *eary);
 char	   *get_comma_elts(eary *eary);
@@ -203,16 +204,37 @@ help(const char *progname)
 void *
 pg_malloc(size_t size)
 {
-	void	   *ptr = malloc(size);
+	void	   *ptr;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
+	ptr = malloc(size);
 	if (!ptr)
 	{
-		fprintf(stderr, "out of memory");
+		fprintf(stderr, "out of memory\n");
 		exit(1);
 	}
 	return ptr;
 }
 
+void *
+pg_realloc(void *ptr, size_t size)
+{
+	void	   *result;
+
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (ptr == NULL && size == 0)
+		size = 1;
+	result = realloc(ptr, size);
+	if (!result)
+	{
+		fprintf(stderr, "out of memory\n");
+		exit(1);
+	}
+	return result;
+}
+
 char *
 pg_strdup(const char *str)
 {
@@ -220,7 +242,7 @@ pg_strdup(const char *str)
 
 	if (!result)
 	{
-		fprintf(stderr, "out of memory");
+		fprintf(stderr, "out of memory\n");
 		exit(1);
 	}
 	return result;
@@ -242,14 +264,8 @@ add_one_elt(char *eltname, eary *eary)
 	else if (eary->num >= eary->alloc)
 	{
 		eary	  ->alloc *= 2;
-		eary	  ->array = (char **)
-		realloc(eary->array, eary->alloc * sizeof(char *));
-
-		if (!eary->array)
-		{
-			fprintf(stderr, "out of memory");
-			exit(1);
-		}
+		eary	  ->array = (char **) pg_realloc(eary->array,
+												 eary->alloc * sizeof(char *));
 	}
 
 	eary	  ->array[eary->num] = pg_strdup(eltname);
diff --git a/contrib/pg_upgrade/util.c b/contrib/pg_upgrade/util.c
index d879e762fa..1d4bc89f0b 100644
--- a/contrib/pg_upgrade/util.c
+++ b/contrib/pg_upgrade/util.c
@@ -192,33 +192,39 @@ get_user_info(char **user_name)
 
 
 void *
-pg_malloc(size_t n)
+pg_malloc(size_t size)
 {
-	void	   *p = malloc(n);
+	void	   *p;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
+	p = malloc(size);
 	if (p == NULL)
 		pg_log(PG_FATAL, "%s: out of memory\n", os_info.progname);
-
 	return p;
 }
 
 void *
-pg_realloc(void *ptr, size_t n)
+pg_realloc(void *ptr, size_t size)
 {
-	void	   *p = realloc(ptr, n);
+	void	   *p;
 
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (ptr == NULL && size == 0)
+		size = 1;
+	p = realloc(ptr, size);
 	if (p == NULL)
 		pg_log(PG_FATAL, "%s: out of memory\n", os_info.progname);
-
 	return p;
 }
 
 
 void
-pg_free(void *p)
+pg_free(void *ptr)
 {
-	if (p != NULL)
-		free(p);
+	if (ptr != NULL)
+		free(ptr);
 }
 
 
diff --git a/contrib/pgbench/pgbench.c b/contrib/pgbench/pgbench.c
index 509472262b..a669cf406b 100644
--- a/contrib/pgbench/pgbench.c
+++ b/contrib/pgbench/pgbench.c
@@ -299,6 +299,9 @@ pg_malloc(size_t size)
 {
 	void	   *result;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	result = malloc(size);
 	if (!result)
 	{
@@ -313,6 +316,9 @@ pg_realloc(void *ptr, size_t size)
 {
 	void	   *result;
 
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (ptr == NULL && size == 0)
+		size = 1;
 	result = realloc(ptr, size);
 	if (!result)
 	{
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 48652b21ea..6b202e0425 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -3358,6 +3358,9 @@ guc_malloc(int elevel, size_t size)
 {
 	void	   *data;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	data = malloc(size);
 	if (data == NULL)
 		ereport(elevel,
@@ -3371,6 +3374,9 @@ guc_realloc(int elevel, void *old, size_t size)
 {
 	void	   *data;
 
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (old == NULL && size == 0)
+		size = 1;
 	data = realloc(old, size);
 	if (data == NULL)
 		ereport(elevel,
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index 11ff554d79..c56f721e08 100644
--- a/src/bin/initdb/initdb.c
+++ b/src/bin/initdb/initdb.c
@@ -294,6 +294,9 @@ pg_malloc(size_t size)
 {
 	void	   *result;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	result = malloc(size);
 	if (!result)
 	{
diff --git a/src/bin/pg_basebackup/streamutil.c b/src/bin/pg_basebackup/streamutil.c
index b6cc2a303e..22f4128180 100644
--- a/src/bin/pg_basebackup/streamutil.c
+++ b/src/bin/pg_basebackup/streamutil.c
@@ -54,6 +54,9 @@ pg_malloc0(size_t size)
 {
 	void	   *result;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	result = malloc(size);
 	if (!result)
 	{
diff --git a/src/bin/pg_ctl/pg_ctl.c b/src/bin/pg_ctl/pg_ctl.c
index 6d74a154ab..23c47f6275 100644
--- a/src/bin/pg_ctl/pg_ctl.c
+++ b/src/bin/pg_ctl/pg_ctl.c
@@ -233,6 +233,9 @@ pg_malloc(size_t size)
 {
 	void	   *result;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	result = malloc(size);
 	if (!result)
 	{
diff --git a/src/bin/pg_dump/dumpmem.c b/src/bin/pg_dump/dumpmem.c
index 22637e26e4..08e82b269d 100644
--- a/src/bin/pg_dump/dumpmem.c
+++ b/src/bin/pg_dump/dumpmem.c
@@ -42,6 +42,9 @@ pg_malloc(size_t size)
 {
 	void	   *tmp;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	tmp = malloc(size);
 	if (!tmp)
 		exit_horribly(NULL, "out of memory\n");
@@ -63,6 +66,9 @@ pg_realloc(void *ptr, size_t size)
 {
 	void	   *tmp;
 
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (ptr == NULL && size == 0)
+		size = 1;
 	tmp = realloc(ptr, size);
 	if (!tmp)
 		exit_horribly(NULL, "out of memory\n");
diff --git a/src/bin/psql/common.c b/src/bin/psql/common.c
index 1cb30088c4..179c162279 100644
--- a/src/bin/psql/common.c
+++ b/src/bin/psql/common.c
@@ -60,6 +60,9 @@ pg_malloc(size_t size)
 {
 	void	   *tmp;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	tmp = malloc(size);
 	if (!tmp)
 	{
diff --git a/src/bin/scripts/common.c b/src/bin/scripts/common.c
index 4a7d02f777..7d8875d81c 100644
--- a/src/bin/scripts/common.c
+++ b/src/bin/scripts/common.c
@@ -304,6 +304,9 @@ pg_malloc(size_t size)
 {
 	void	   *tmp;
 
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
 	tmp = malloc(size);
 	if (!tmp)
 	{
diff --git a/src/port/dirmod.c b/src/port/dirmod.c
index 22f5c591b0..514424f82e 100644
--- a/src/port/dirmod.c
+++ b/src/port/dirmod.c
@@ -70,7 +70,11 @@ fe_palloc(Size size)
 {
 	void	   *res;
 
-	if ((res = malloc(size)) == NULL)
+	/* Avoid unportable behavior of malloc(0) */
+	if (size == 0)
+		size = 1;
+	res = malloc(size);
+	if (res == NULL)
 	{
 		fprintf(stderr, _("out of memory\n"));
 		exit(1);
@@ -96,7 +100,11 @@ fe_repalloc(void *pointer, Size size)
 {
 	void	   *res;
 
-	if ((res = realloc(pointer, size)) == NULL)
+	/* Avoid unportable behavior of realloc(NULL, 0) */
+	if (pointer == NULL && size == 0)
+		size = 1;
+	res = realloc(pointer, size);
+	if (res == NULL)
 	{
 		fprintf(stderr, _("out of memory\n"));
 		exit(1);