diff --git a/configure.ac b/configure.ac
index 1ef51d6..1aa1a7d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -23,6 +23,7 @@ AX_PREFIX_CONFIG_H([include/libsemigroups/libsemigroups-config.hpp],[],[config/c
 AC_PROG_CXX
 AC_LANG([C++])
 AX_CXX_COMPILE_STDCXX_11(,[mandatory])
+AC_LANG_PUSH([C])
 
 dnl ## Check for pthread, this seems to be required to compile with GCC
 AX_PTHREAD(,[AC_MSG_ERROR([pthread is required])])
@@ -53,6 +54,7 @@ AC_CHECK_SIZEOF([void *])
 # Checks for library functions.
 AC_FUNC_MALLOC
 AC_CHECK_FUNCS([gettimeofday memset pow sqrt])
+AC_LANG_POP([C])
 
 # Check if debug mode is enabled
 AC_ARG_ENABLE([debug],