Add AM_PROG_CC_C_O to configure.ac

Recent autoconf has complained about the lack of this

Add AM_PROG_CC_C_O to configure.ac
Recent autoconf has complained about the lack of this
df46022b · Lorenz Huedepohl · 6e973ae5 · df46022b
Commit df46022b authored Jun 14, 2016 by Lorenz Huedepohl
--- a/configure.ac
+++ b/configure.ac
@@ -95,6 +95,7 @@ fi
 AC_PROG_INSTALL
 AM_PROG_AR
 AM_PROG_AS
+AM_PROG_CC_C_O

 # Fortran
 AC_LANG([Fortran])