From e2cfed3377aa2a46de81eea19876cbb7c69350ae Mon Sep 17 00:00:00 2001
From: Christophe CURIS <christophe.curis@free.fr>
Date: Sat, 4 May 2019 14:58:48 +0200
Subject: [PATCH] Do not stop compilation if library Xmu is not found

We use only 1 function from this library, and it is in a case that should
be rare nowadays: displays with indexed color.
This commit makes it acceptable to compile if the library is missing.
---
 NEWS                | 10 ++++++++++
 m4/wm_xext_check.m4 | 26 ++++++++++++++++----------
 wrlib/context.c     | 10 ++++++++++
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/NEWS b/NEWS
index b469a9ca..8ed766f6 100644
--- a/NEWS
+++ b/NEWS
@@ -12,6 +12,16 @@ which defaulted to ~/GNUstep.  However, this environment variable was deprecated
 in gnustep-make v2.  Therefore, it has been replaced by the WMAKER_USER_ROOT
 environment variable.
 
+
+libXmu is now an optional dependency
+------------------------------------
+
+If the library is not found, compilation work, the only limitation will arise
+when trying to install the standard colormap on displays which are not TrueColor.
+Please note that if you have the library but not the headers, configure will
+still stop; there is no user option to explicitly disable the library use.
+
+
 -- 0.95.8
 
 Move pointer with maximized windows
diff --git a/m4/wm_xext_check.m4 b/m4/wm_xext_check.m4
index cf6c70ff..8bcaf8c9 100644
--- a/m4/wm_xext_check.m4
+++ b/m4/wm_xext_check.m4
@@ -90,12 +90,11 @@ AC_DEFUN_ONCE([WM_EXT_CHECK_XMU],
      AS_IF([wm_fn_lib_try_link "XmuLookupStandardColormap" "-lXmu"],
          [wm_cv_xext_xmu="-lXmu"])
      LIBS="$wm_save_LIBS"
-     AS_IF([test "x$wm_cv_xext_xmu" = "xno"],
-         [AC_MSG_ERROR([library Xmu not found])])
-     dnl
-     dnl A library was found, check if header is available and compile
-     wm_save_CFLAGS="$CFLAGS"
-     AC_COMPILE_IFELSE([AC_LANG_PROGRAM([dnl
+     AS_IF([test "x$wm_cv_xext_xmu" != "xno"],
+       [dnl
+       dnl A library was found, check if header is available and compile
+       wm_save_CFLAGS="$CFLAGS"
+       AC_COMPILE_IFELSE([AC_LANG_PROGRAM([dnl
 @%:@include <X11/Xlib.h>
 @%:@include <X11/Xutil.h>
 @%:@include <X11/Xmu/StdCmap.h>
@@ -104,11 +103,18 @@ Display *dpy;
 Atom prop;
 ], [dnl
   XmuLookupStandardColormap(dpy, 0, 0, 0, prop, False, True);]) ],
-         [],
-         [AC_MSG_ERROR([found $wm_cv_xext_xmu but cannot compile with the header])])
-     CFLAGS="$wm_save_CFLAGS"])
+           [],
+           [AC_MSG_ERROR([found $wm_cv_xext_xmu but cannot compile with the header])])
+       CFLAGS="$wm_save_CFLAGS"])
+    ])
 dnl The cached check already reported problems when not found
-LIBXMU="$wm_cv_xext_xmu"
+AS_IF([test "wm_cv_xext_xmu" = "xno"],
+  [LIBXMU=""
+   unsupported="$unsupported Xmu"],
+  [AC_DEFINE([HAVE_LIBXMU], [1],
+       [defined when the libXmu library was found])
+   LIBXMU="$wm_cv_xext_xmu"
+   supported_xext="$supported_xext Xmu"])
 AC_SUBST(LIBXMU)dnl
 ])
 
diff --git a/wrlib/context.c b/wrlib/context.c
index ee0b9931..8e30a63f 100644
--- a/wrlib/context.c
+++ b/wrlib/context.c
@@ -25,7 +25,10 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/Xatom.h>
+
+#ifdef HAVE_LIBXMU
 #include <X11/Xmu/StdCmap.h>
+#endif
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -137,6 +140,7 @@ static Bool allocateStandardPseudoColor(RContext * ctx, XStandardColormap * stdc
 
 static Bool setupStandardColormap(RContext * ctx, Atom property)
 {
+#ifdef HAVE_LIBXMU
 	if (!XmuLookupStandardColormap(ctx->dpy, ctx->screen_number,
 				       ctx->visual->visualid, ctx->depth, property, True, True)) {
 		RErrorCode = RERR_STDCMAPFAIL;
@@ -144,6 +148,12 @@ static Bool setupStandardColormap(RContext * ctx, Atom property)
 		return False;
 	}
 	return True;
+#else
+	(void) ctx;
+	(void) property;
+	RErrorCode = RERR_STDCMAPFAIL;
+	return False;
+#endif
 }
 
 static XColor *allocateColor(RContext *ctx, XColor *colors, int ncolors)
-- 
2.11.4.GIT