configure: various fixes regarding compiler flags

First attempt at setting certain -Defines and compiler flags (like
-fno-strict-aliasing).  Only linux for now.

Add CSRG_BASED to CPP_SOURCE_FLAGS rather than directly at CFLAGS.
This will be added to CFLAGS later on in the script along with other
gathered flags and options.

Set CFLAGS, CXXFLAGS, and CPPFLAGS at the end, composed of other env
variables we set earlier on.

cde/configure.ac

@@ -20,8 +20,21 @@ AC_SUBST(MAJOR)
 AC_SUBST(MINOR)
 AC_SUBST(MICRO)
 
-dnl These OS checks are deprecated and should be replaced with feature checks
-dnl where appropriate
+dnl SOURCE_DEFINES - needed for some OS's
+SOURCE_CPP_DEFINES=""
+
+dnl CPP_COMPILER_FLAGS - CPP/C/C++ compiler flags
+CPP_COMPILER_FLAGS=""
+
+dnl CXX_COMPILER_FLAGS - C++ compiler flags
+CXX_COMPILER_FLAGS=""
+
+dnl C_COMPILER_FLAGS - C compiler flags
+C_COMPILER_FLAGS=""
+
+
+dnl These OS version checks are deprecated and should be replaced with
+dnl feature checks where appropriate
 
 build_linux=no
 bsd=no
@@ -38,37 +51,41 @@ dnl choose defaults here.  These need to be removed in the code in favor
 dnl of actual checks for functionality. So this should be considered
 dnl temporary.
 
-osmajorversion=4
-osminorversion=15
+OSMAJORVERSION=4
+OSMINORVERSION=15
 
 case "${host_os}" in
 	linux*)
 		build_linux=yes
-                osmajorversion=4
-                osminorversion=15
-		;;
+                OSMAJORVERSION=4
+                OSMINORVERSION=15
+                SOURCE_CPP_DEFINES="-D_POSIX_SOURCE -D_DEFAULT_SOURCE \
+-D_BSD_SOURCE -D_SVID_SOURCE"
+                CPP_COMPILER_FLAGS="-fno-strict-aliasing -Wno-write-strings \
+-Wno-unused-result"
+                 ;;
 	freebsd*)
 		build_freebsd=yes
 		bsd=yes
-                osmajorversion=10
-                osminorversion=0
+                OSMAJORVERSION=10
+                OSMINORVERSION=0
 		;;
 	openbsd*)
 		build_openbsd=yes
 		bsd=yes
-                osmajorversion=6
-                osminorversion=2
+                OSMAJORVERSION=6
+                OSMINORVERSION=2
 		;;
 	netbsd*)
 		build_netbsd=yes
 		bsd=yes
-                osmajorversion=8
-                osminorversion=0
+                OSMAJORVERSION=8
+                OSMINORVERSION=0
 		;;
 	solaris*|sun*)
 		build_solaris=yes
-                osmajorversion=5
-                osminorversion=10
+                OSMAJORVERSION=5
+                OSMINORVERSION=10
 		;;
 	aix*)
 		build_aix=yes
@@ -88,16 +105,12 @@ AM_CONDITIONAL([AIX], [test "$build_aix" = "yes"])
 AM_CONDITIONAL([HPUX], [test "$build_hpux" = "yes"])
 
 dnl Add osmajor/minor version to cppflags.
-oflags="$CPPFLAGS"
-CPPFLAGS="$oflags -DOSMAJORVERSION=$osmajorversion \
-                  -DOSMINORVERSION=$osminorversion"
-
+OSVERSION="-DOSMAJORVERSION=$OSMAJORVERSION -DOSMINORVERSION=$OSMINORVERSION"
 
 dnl set CSRG_BASED define for the BSD's
 if test "$build_bsd" = "yes"
 then
-        oflags="$CPPFLAGS"
-        CPPFLAGS="$oflags -DCSRG_BASED"
+        SOURCE_CPP_DEFINES="${SOURCE_CPP_DEFINES} -DCSRG_BASED"
 fi
 
 is_x86_64=no
@@ -136,7 +149,7 @@ AM_CONDITIONAL([MIPS], [test "is_mips" = yes])
 AM_CONDITIONAL([PPC], [test "is_ppc" = yes])
 
 dnl our main libraries
-dnl we use single quotes so that $top_builder is evaluated in the makfiles,
+dnl we use single quotes so that $top_builder is evaluated in the makefiles,
 dnl not here.
 AC_SUBST(LIBTT, '$(top_builddir)/lib/tt/lib/libtt.la')
 AC_SUBST(LIBXIN, '$(top_builddir)/lib/DtXinerama/libDtXinerama.a')
@@ -230,6 +243,12 @@ AC_CHECK_LIB(tirpc, main, [TIRPCINC="-DOPT_TIRPC -I/usr/include/tirpc"; TIRPCLIB
 AC_SUBST(TIRPCINC)
 AC_SUBST(TIRPCLIB)
 
+
+dnl set CPPFLAGS, CFLAGS, and CXXFLAGS
+CPPFLAGS="${CPPFLAGS} ${SOURCE_CPP_DEFINES} ${CPP_COMPILER_FLAGS} ${OSVERSION}"
+CFLAGS="${CFLAGS} ${C_COMPILER_FLAGS}"
+CXXFLAGS="${CXXFLAGS} ${CXX_COMPILER_FLAGS}"
+
 dnl All of the makefiles we need to generate go here...
 AC_CONFIG_FILES([
 Makefile