build: call AM_PROG_CC_C_O as requested by autoreconf

diff --git a/configure.in b/configure.in
index 64f9cbe57a96ae6b720569fa55c7c0f7f06ce56b..da50fdd9899262d82dbd0c5acb0e6dbacf91a1c6 100644 (file)
--- a/configure.in
+++ b/configure.in
@@ -20,6 +20,7 @@ AM_CONDITIONAL(ENABLE_OLDNAME_COMPAT, [test "x${enable_oldname_compat}" != "xno"
 # Checks for libraries.
 
 # Checks for header files.
+AM_PROG_CC_C_O
 AC_CONFIG_HEADER(config.h)
 AC_CONFIG_HEADER(json_config.h)
 AC_HEADER_STDC