configure.ac: Add test for c++ compiler.

The AC_PROG_CXX macro sets a flag if a C++ compiler is found
but does not fail if one is not found, it left to application
to test the flags as needed. This fix will issue an error
when a c++ compiler is not found.  Bug 3955.

Signed-off-by: Gary Lowell  <gary.lowell@inktank.com>
it's not installed, this fix adds an error message for a

diff --git a/configure.ac b/configure.ac
index eeed31fd55cbb5fc11350b1852df6125df642589..2d445e55b0fac083ba0982bad2cb348ced38b1aa 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -56,6 +56,10 @@ AM_CONDITIONAL(FREEBSD, test x"$freebsd" = x"yes")
 
 # Checks for programs.
 AC_PROG_CXX
+if test "$CXX" = no || test "$CXX:$GXX" = "g++:"; then
+  AC_MSG_ERROR([no C++ compiler found])
+fi
+
 #AC_PROG_CC
 AC_PROG_MAKE_SET
 AC_PROG_LIBTOOL