--- gprolog-1.5.0.orig/src/configure.in	2021-07-08 09:34:44.000000000 -0000
+++ gprolog-1.5.0/src/configure.in	2021-07-10 16:25:44.397630093 -0000
@@ -342,15 +342,26 @@
 dnl we use AS0 instead of AS else AC_CHECK_TOOL does not work 
 dnl (instead of testing a prefix like x86_64-w64-mingw32- it will
 dnl think the user wants to override the test)
-    AS0=as
-    case "$host" in
-        sparc64*bsd*)    ASFLAGS='-Av9a -64 -K PIC';;
-        i*86*darwin1*)   ASFLAGS='-arch i686';;
-        i*86*linux*)     ASFLAGS='--32';;
-        x86_64*solaris*) AS0=gas; ASFLAGS='--64';;
-        x86_64*darwin*)  ASFLAGS='-arch x86_64';;
-        x86_64*linux*)   ASFLAGS='--64';;
-        *)               if test "$with_gas" = yes; then AS0=gas; fi;;
+    case "$CC" in
+        *cc)
+            AS0=as
+            case "$host" in
+                sparc64*bsd*)    ASFLAGS='-Av9a -64 -K PIC';;
+                i*86*darwin1*)   ASFLAGS='-arch i686';;
+                i*86*linux*)     ASFLAGS='--32';;
+                x86_64*solaris*) AS0=gas; ASFLAGS='--64';;
+                x86_64*darwin*)  ASFLAGS='-arch x86_64';;
+                x86_64*linux*)   ASFLAGS='--64';;
+                *)               if test "$with_gas" = yes; then AS0=gas; fi;;
+            esac
+            ;;
+        *clang)
+            AS0=$CC
+            ASFLAGS='-c'
+            ;;
+        *)
+            AC_MSG_ERROR([unsupported compiler $CC])
+            ;;
     esac
     AC_CHECK_TOOL([AS],[$AS0])
     AC_PROG_RANLIB