--- potrace-1.15/configure.ac.orig 2017-12-01 07:10:43.783207400 +0300 +++ potrace-1.15/configure.ac 2017-12-01 07:10:59.491835900 +0300 @@ -28,7 +28,7 @@ dnl figure out compiler options dnl Check for compiler -AC_PROG_CC([clang gcc cc c99 mgcc c89 pcc opencc sunc99 suncc]) +AC_PROG_CC([gcc cc c99 mgcc c89 pcc opencc sunc99 suncc clang]) dnl Also add CADD to the CFLAGS at configure time or compile time AC_SUBST(CADD)