* configure.ac (HAVE_XPM): Explain the use of CPPFLAGS in the Cygwin-w32 build. (Bug#18302)

2 files changed, 8 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 069b3545e0f..b9c2039d57c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-08-21  Ken Brown  <kbrown@cornell.edu>
+
+        * configure.ac (HAVE_XPM): Explain the use of CPPFLAGS in the
+        Cygwin-w32 build.  (Bug#18302)
+
 2014-08-11  Paul Eggert  <eggert@cs.ucla.edu>
 
         Don't prevent random file systems from being unmounted (Bug#18232).
diff --git a/configure.ac b/configure.ac
index 3e49527e0f1..806b1b4f308 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2991,6 +2991,9 @@ AC_SUBST(M17N_FLT_LIBS)
 
 ### Use -lXpm if available, unless `--with-xpm=no'.
 ### mingw32 doesn't use -lXpm, since it loads the library dynamically.
+### In the Cygwin-w32 build, we need to use /usr/include/noX/X11/xpm.h
+### rather than /usr/include/X11/xpm.h, so we set CPPFLAGS (and
+### LDFLAGS) accordingly.
 HAVE_XPM=no
 LIBXPM=
 if test "${HAVE_W32}" = "yes" && test "${opsys}" = "cygwin"; then