Replace SYSTEMQUOTEs with Windows-specific wrapper functions.

It's easy to forget using SYSTEMQUOTEs when constructing command strings
for system() or popen(). Even if we fix all the places missing it now, it is
bound to be forgotten again in the future. Introduce wrapper functions that
do the the extra quoting for you, and get rid of SYSTEMQUOTEs in all the
callers.

We previosly used SYSTEMQUOTEs in all the hard-coded command strings, and
this doesn't change the behavior of those. But user-supplied commands, like
archive_command, restore_command, COPY TO/FROM PROGRAM calls, as well as
pgbench's \shell, will now gain an extra pair of quotes. That is desirable,
but if you have existing scripts or config files that include an extra
pair of quotes, those might need to be adjusted.

Reviewed by Amit Kapila and Tom Lane

src/interfaces/ecpg/test/pg_regress_ecpg.c

@@ -137,7 +137,7 @@ ecpg_start_test(const char *testname,
 	snprintf(inprg, sizeof(inprg), "%s/%s", inputdir, testname);
 
 	snprintf(cmd, sizeof(cmd),
-			 SYSTEMQUOTE "\"%s\" >\"%s\" 2>\"%s\"" SYSTEMQUOTE,
+			 "\"%s\" >\"%s\" 2>\"%s\"",
 			 inprg,
 			 outfile_stdout,
 			 outfile_stderr);

src/interfaces/libpq/Makefile

@@ -38,7 +38,7 @@ OBJS=	fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
 OBJS += chklocale.o inet_net_ntop.o noblock.o pgstrcasecmp.o pqsignal.o \
 	thread.o
 # libpgport C files that are needed if identified by configure
-OBJS += $(filter crypt.o getaddrinfo.o getpeereid.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o win32setlocale.o, $(LIBOBJS))
+OBJS += $(filter crypt.o getaddrinfo.o getpeereid.o inet_aton.o open.o system.o snprintf.o strerror.o strlcpy.o win32error.o win32setlocale.o, $(LIBOBJS))
 # backend/libpq
 OBJS += ip.o md5.o
 # utils/mb
@@ -89,7 +89,7 @@ backend_src = $(top_srcdir)/src/backend
 # For some libpgport modules, this only happens if configure decides
 # the module is needed (see filter hack in OBJS, above).
 
-chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c inet_net_ntop.c noblock.c open.c pgsleep.c pgstrcasecmp.c pqsignal.c snprintf.c strerror.c strlcpy.c thread.c win32error.c win32setlocale.c: % : $(top_srcdir)/src/port/%
+chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c inet_net_ntop.c noblock.c open.c system.c pgsleep.c pgstrcasecmp.c pqsignal.c snprintf.c strerror.c strlcpy.c thread.c win32error.c win32setlocale.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 ip.c md5.c: % : $(backend_src)/libpq/%
@@ -150,7 +150,7 @@ clean distclean: clean-lib
 # Might be left over from a Win32 client-only build
 	rm -f pg_config_paths.h
 	rm -f inet_net_ntop.c noblock.c pgstrcasecmp.c pqsignal.c thread.c
-	rm -f chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c open.c snprintf.c strerror.c strlcpy.c win32error.c win32setlocale.c
+	rm -f chklocale.c crypt.c getaddrinfo.c getpeereid.c inet_aton.c open.c system.c snprintf.c strerror.c strlcpy.c win32error.c win32setlocale.c
 	rm -f pgsleep.c
 	rm -f md5.c ip.c
 	rm -f encnames.c wchar.c

src/interfaces/libpq/bcc32.mak

@@ -106,6 +106,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\system.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
 	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -149,6 +150,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\system.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\pthread-win32.obj"
 
@@ -295,6 +297,11 @@ LINK32_FLAGS = -Gn -L$(BCB)\lib;$(INTDIR); -x -Tpd -v
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\system.obj" : ..\..\port\system.c
+	$(CPP) @<<
+	$(CPP_PROJ) /I"." ..\..\port\system.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c

src/interfaces/libpq/win32.mak

@@ -113,6 +113,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\system.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(INTDIR)\win32setlocale.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
@@ -159,6 +160,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\system.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\win32setlocale.obj" \
 	"$(INTDIR)\pthread-win32.obj"
@@ -335,6 +337,11 @@ LINK32_OBJS= \
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\system.obj" : ..\..\port\system.c
+	$(CPP) @<<
+	$(CPP_PROJ) /I"." ..\..\port\system.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c