Undo some (unnecessary) changes.

(cherry picked from commit fc657184a0)

app/config/Makefile.am

@@ -15,7 +15,7 @@ endif
 AM_CPPFLAGS = \
 	-DG_LOG_DOMAIN=\"Gimp-Config\"				\
 	-DGIMP_APP_VERSION_STRING=\"$(GIMP_APP_VERSION)\"	\
-	-DGIMPDATADIR=\""$(datadir)"\"				\
+	-DDATADIR=\""$(datadir)"\"				\
 	-I$(top_builddir)					\
 	-I$(top_srcdir)						\
 	-I$(top_builddir)/app					\

plug-ins/help/Makefile.am

@@ -17,7 +17,7 @@ help_RC = help.rc.o
 endif
 
 AM_CPPFLAGS = \
-	-DGIMPDATADIR=\""$(gimpdatadir)"\"	\
+	-DDATADIR=\""$(gimpdatadir)"\"	\
 	-I$(top_srcdir)			\
 	$(CAIRO_CFLAGS)			\
 	$(GIO_CFLAGS)			\

tools/Makefile.am

@@ -73,7 +73,7 @@ AM_CPPFLAGS = \
 	-DBINDIR=\""$(bindir)"\"				\
 	-DSBINDIR=\""$(sbindir)"\"				\
 	-DLIBEXECDIR=\""$(libexecdir)"\"			\
-	-DSYSDATADIR=\""$(datadir)"\"				\
+	-DDATADIR=\""$(datadir)"\"				\
 	-DDATAROOTDIR=\""$(datarootdir)"\"			\
 	-DSYSCONFDIR=\""$(sysconfdir)"\"			\
 	-DSHAREDSTATEDIR=\""$(sharedstatedir)"\"		\

tools/gimptool.c

@@ -75,7 +75,7 @@ static struct {
   { "bindir",         BINDIR         },
   { "sbindir",        SBINDIR        },
   { "libexecdir",     LIBEXECDIR     },
-  { "datadir",        SYSDATADIR     },
+  { "datadir",        DATADIR        },
   { "datarootdir",    DATAROOTDIR    },
   { "sysconfdir",     SYSCONFDIR     },
   { "sharedstatedir", SHAREDSTATEDIR },