[RFC/PATCH] autoconf: Do not build "http-push" without expat headers

Simply linking against expat does not guarantee successful compilation.
Check for development headers before attempting to compile the dependant
binaries.

Signed-off-by: Allan Caffee <redacted>
---
 configure.ac |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/configure.ac b/configure.ac
index 4e728bc..3de0ae7 100644
--- a/configure.ac
+++ b/configure.ac

@@ -375,6 +375,9 @@ GIT_STASH_FLAGS($EXPATDIR)
 AC_CHECK_LIB([expat], [XML_ParserCreate],
 [NO_EXPAT=],
 [NO_EXPAT=YesPlease])
+AC_CHECK_HEADER([expat.h],
+[NO_EXPAT=],
+[NO_EXPAT=YesPlease])
 
 GIT_UNSTASH_FLAGS($EXPATDIR)
 

-- 
1.5.6.3