configure: combine common parts of CONFIGURE_C{,XX}FLAGS

By combining the common parts of CONFIGURE_CFLAGS and CONFIGURE_CXXFLAGS
to a separate make variable and using that as part of their
definitions makes setting of these easier, DRYer and less error prone
(especially as we cannot check potential typing errors there).

configure

@@ -1084,11 +1084,11 @@ WITH_BASH = ${WITH_BASH}
 WITH_ZSH = ${WITH_ZSH}
 
 # Combined flags for compiling and linking against all of the above
-CONFIGURE_CFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)      \\
+COMMON_CONFIGURE_CFLAGS = \\
+	\$(GMIME_CFLAGS) \$(TALLOC_CFLAGS) \$(ZLIB_CFLAGS)	\\
+	-DHAVE_VALGRIND=\$(HAVE_VALGRIND) \$(VALGRIND_CFLAGS)	\\
+	-DHAVE_GETLINE=\$(HAVE_GETLINE)				\\
 	-DHAVE_CANONICALIZE_FILE_NAME=\$(HAVE_CANONICALIZE_FILE_NAME) \\
-		   \$(ZLIB_CFLAGS)					 \\
-		   \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND)   \\
-		   \$(VALGRIND_CFLAGS)                                   \\
 	-DHAVE_STRCASESTR=\$(HAVE_STRCASESTR)			\\
 	-DHAVE_STRSEP=\$(HAVE_STRSEP)				\\
 	-DHAVE_TIMEGM=\$(HAVE_TIMEGM)				\\
@@ -1099,20 +1099,9 @@ CONFIGURE_CFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)      \\
 	-DHAVE_XAPIAN_FIELD_PROCESSOR=\$(HAVE_XAPIAN_FIELD_PROCESSOR) \\
 	-DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER)
 
-CONFIGURE_CXXFLAGS = -DHAVE_GETLINE=\$(HAVE_GETLINE) \$(GMIME_CFLAGS)    \\
-		     -DHAVE_CANONICALIZE_FILE_NAME=\$(HAVE_CANONICALIZE_FILE_NAME) \\
-		     \$(ZLIB_CFLAGS)					 \\
-		     \$(TALLOC_CFLAGS) -DHAVE_VALGRIND=\$(HAVE_VALGRIND) \\
-		     \$(VALGRIND_CFLAGS) \$(XAPIAN_CXXFLAGS)             \\
-		     -DHAVE_STRCASESTR=\$(HAVE_STRCASESTR)               \\
-		     -DHAVE_STRSEP=\$(HAVE_STRSEP)                       \\
-		     -DHAVE_TIMEGM=\$(HAVE_TIMEGM)                       \\
-		     -DHAVE_D_TYPE=\$(HAVE_D_TYPE)                       \\
-		     -DSTD_GETPWUID=\$(STD_GETPWUID)                     \\
-		     -DSTD_ASCTIME=\$(STD_ASCTIME)                       \\
-		     -DHAVE_XAPIAN_COMPACT=\$(HAVE_XAPIAN_COMPACT)       \\
-		     -DHAVE_XAPIAN_FIELD_PROCESSOR=\$(HAVE_XAPIAN_FIELD_PROCESSOR) \\
-		     -DUTIL_BYTE_ORDER=\$(UTIL_BYTE_ORDER)
+CONFIGURE_CFLAGS = \$(COMMON_CONFIGURE_CFLAGS)
+
+CONFIGURE_CXXFLAGS = \$(COMMON_CONFIGURE_CFLAGS) \$(XAPIAN_CXXFLAGS)
 
 CONFIGURE_LDFLAGS =  \$(GMIME_LDFLAGS) \$(TALLOC_LDFLAGS) \$(ZLIB_LDFLAGS) \$(XAPIAN_LDFLAGS)
 EOF