Pacify Clang w.r.t. unknown compiler flags.

	* configure.ac: Do not add `-Wno-unused-local-typedefs' to
	WARNINGS_CXXFLAGS if it is accepted by the compiler but produces a
	warning.

ChangeLog

+2014-07-03  Roland Levillain  <roland@lrde.epita.fr>
+
+	Pacify Clang w.r.t. unknown compiler flags.
+
+	* configure.ac: Do not add `-Wno-unused-local-typedefs' to
+	WARNINGS_CXXFLAGS if it is accepted by the compiler but produces a
+	warning.
+
 2014-07-03  Roland Levillain  <roland@lrde.epita.fr>
 
 	Help configure find Poppler on OS X with the MacPorts.

configure.ac

@@ -110,7 +110,8 @@ esac
 # concept checking means in Milena (`-Wunused-local-typedefs' is
 # enabled by `-Wall' in GCC since version 4.8).
 AX_CHECK_COMPILE_FLAG([-Wno-unused-local-typedefs],
-  [WARNINGS_CXXFLAGS="$WARNINGS_CXXFLAGS -Wno-unused-local-typedefs"])
+  [WARNINGS_CXXFLAGS="$WARNINGS_CXXFLAGS -Wno-unused-local-typedefs"], [:],
+  [-Werror])
 
 
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