MinGW: Link with shell32.dll instead of shfolder.dll.

This improves consistency with the MSVC build.  On buildfarm member
narwhal, since commit 846e91e0,
shfolder.dll:SHGetFolderPath() crashes when dblink calls it by way of
pqGetHomeDirectory().  Back-patch to 9.4, where that commit first
appeared.  How it caused this regression remains a mystery.  This is a
partial revert of commit 889f0381, which
adopted shfolder.dll for Windows NT 4.0 compatibility.  PostgreSQL 8.2
dropped support for that operating system.

src/Makefile.global.in

@@ -549,10 +549,9 @@ LIBOBJS = @LIBOBJS@
 
 LIBS := -lpgcommon -lpgport $(LIBS)
 
-# to make ws2_32.lib the last library, and always link with shfolder,
-# so SHGetFolderName isn't picked up from shell32.dll
+# to make ws2_32.lib the last library
 ifeq ($(PORTNAME),win32)
-LIBS += -lws2_32 -lshfolder
+LIBS += -lws2_32
 endif
 
 # Not really standard libc functions, used by the backend.

src/interfaces/ecpg/ecpglib/Makefile

@@ -39,11 +39,6 @@ SHLIB_PREREQS = submake-libpq submake-pgtypeslib
 
 SHLIB_EXPORTS = exports.txt
 
-ifeq ($(PORTNAME), win32)
-# Link to shfolder.dll instead of shell32.dll
-SHLIB_LINK += -lshfolder
-endif
-
 PKG_CONFIG_REQUIRES_PRIVATE = libpq libpgtypes
 
 all: all-lib

src/interfaces/libpq/Makefile

@@ -74,7 +74,7 @@ else
 SHLIB_LINK += $(filter -lcrypt -ldes -lcom_err -lcrypto -lk5crypto -lkrb5 -lgssapi32 -lssl -lsocket -lnsl -lresolv -lintl $(PTHREAD_LIBS), $(LIBS)) $(LDAP_LIBS_FE)
 endif
 ifeq ($(PORTNAME), win32)
-SHLIB_LINK += -lshfolder -lws2_32 -lsecur32 $(filter -leay32 -lssleay32 -lcomerr32 -lkrb5_32, $(LIBS))
+SHLIB_LINK += -lshell32 -lws2_32 -lsecur32 $(filter -leay32 -lssleay32 -lcomerr32 -lkrb5_32, $(LIBS))
 endif
 
 SHLIB_EXPORTS = exports.txt

src/interfaces/libpq/win32.mak

@@ -214,7 +214,7 @@ CPP_SBRS=.
 RSC_PROJ=/l 0x409 /fo"$(INTDIR)\libpq.res"
 
 LINK32=link.exe
-LINK32_FLAGS=kernel32.lib user32.lib advapi32.lib shfolder.lib ws2_32.lib secur32.lib $(SSL_LIBS)  $(KFW_LIB) $(ADD_SECLIB) \
+LINK32_FLAGS=kernel32.lib user32.lib advapi32.lib shell32.lib ws2_32.lib secur32.lib $(SSL_LIBS)  $(KFW_LIB) $(ADD_SECLIB) \
  /nologo /subsystem:windows /dll $(LOPT) /incremental:no \
  /pdb:"$(OUTDIR)\libpqdll.pdb" /machine:$(CPU) \
  /out:"$(OUTDIR)\$(OUTFILENAME).dll"\

src/port/path.c

@@ -785,9 +785,11 @@ get_home_path(char *ret_path)
 	char	   *tmppath;
 
 	/*
-	 * Note: We use getenv here because the more modern
-	 * SHGetSpecialFolderPath() will force us to link with shell32.lib which
-	 * eats valuable desktop heap.
+	 * Note: We use getenv() here because the more modern SHGetFolderPath()
+	 * would force the backend to link with shell32.lib, which eats valuable
+	 * desktop heap.  XXX This function is used only in psql, which already
+	 * brings in shell32 via libpq.  Moving this function to its own file
+	 * would keep it out of the backend, freeing it from this concern.
 	 */
 	tmppath = getenv("APPDATA");
 	if (!tmppath)