Make pgcompinclude/pgrminclude less tied to Bruce's personal machine.

Not everyone has /pg linked to the src subdirectory of their PostgreSQL
tree.  Also, cc isn't the way to invoke the compiler everywhere.

src/tools/pginclude/pgcompinclude

@@ -3,6 +3,9 @@
 # takes -v option to display compile failure message and line numbers
 # src/tools/pginclude/pgcompinclude
 
+: ${CC:=cc}
+: ${PGSRC:=src}
+
 if ! pgdefine
 then	echo "pgdefine must be in your PATH" 1>&2
 	exit 1
@@ -29,9 +32,9 @@ do
 
 	# Use -O1 to get warnings only generated by optimization,
 	# but -O2 is too slow.
-	cc -fsyntax-only -Werror -Wall -Wmissing-prototypes \
-		-Wmissing-declarations -I/pg/include -I/pg/backend \
-		-I/pg/interfaces/libpq -I`dirname $FILE` $CFLAGS -O1 -c /tmp/$$.c \
+	$CC -fsyntax-only -Werror -Wall -Wmissing-prototypes \
+		-Wmissing-declarations -I$PGSRC/include -I$PGSRC/backend \
+		-I$PGSRC/interfaces/libpq -I`dirname $FILE` $CFLAGS -O1 -c /tmp/$$.c \
 		-o /tmp/$$.o >/tmp/$$ 2>&1
 	if [ "$?" -ne 0 ]
 	then	echo "$FILE"

src/tools/pginclude/pgrminclude

@@ -18,6 +18,9 @@
 # be compiled on the platform from which pgrminclude is run cannot be
 # processed, and are skipped.
 
+: ${CC:=cc}
+: ${PGSRC:=src}
+
 if ! pgdefine
 then	echo "pgdefine must be in your PATH" 1>&2
 	exit 1
@@ -104,9 +107,9 @@ compile_file() {
 
 	# Use -O1 to get warnings only generated by optimization,
 	# but -O2 is too slow.
-	cc -fsyntax-only -Werror -Wall -Wmissing-prototypes \
-		-Wmissing-declarations -I/pg/include -I/pg/backend \
-		-I/pg/interfaces/libpq -I`dirname $FILE` $CFLAGS -O1 -c /tmp/$$.c \
+	$CC -fsyntax-only -Werror -Wall -Wmissing-prototypes \
+		-Wmissing-declarations -I$PGSRC/include -I$PGSRC/backend \
+		-I$PGSRC/interfaces/libpq -I`dirname $FILE` $CFLAGS -O1 -c /tmp/$$.c \
 		-o /tmp/$$.o >/tmp/$$ 2>&1
 	if [ "$?" -eq 0 ]
 	then	[ "$INCLUDE" -o "$VERBOSE" ] && echo "$FILE $INCLUDE"