Merge pull request #1622 from goshhhy/aix

fix building ninja_test on AIX 6.1
diff --git a/src/test.cc b/src/test.cc
index a9816bc..8ba2297 100644
--- a/src/test.cc
+++ b/src/test.cc
@@ -33,6 +33,15 @@
 #include "manifest_parser.h"
 #include "util.h"
 
+#ifdef _AIX
+extern "C" {
+        // GCC "helpfully" strips the definition of mkdtemp out on AIX.
+        // The function is still present, so if we define it ourselves
+        // it will work perfectly fine.
+        extern char* mkdtemp(char* name_template);
+}
+#endif
+
 namespace {
 
 #ifdef _WIN32