Fix compilation with MSVC 2022

On MSVC, log is an intrinsic that doesn't require libm. However,
AC_SEARCH_LIBS does not successfully detect this, as it will try to
compile a program using the wrong signature for log. Newer versions of
MSVC CL detects this and rejects the program with the following
messages:

conftest.c(40): warning C4391: 'char log()': incorrect return type for intrinsic function, expected 'double'
conftest.c(44): error C2168: 'log': too few actual parameters for intrinsic function

Since log is always available on MSVC (it's been around since the dawn
of time), we simply always assume it's there if MSVC is detected.

Signed-off-by: roblabla <[email protected]>

Author: roblabla

configure.ac

@@ -829,11 +829,26 @@ AC_SUBST([DUMP_SYMS])
 AC_SUBST([CC_MM])
 
 dnl Determine whether libm must be linked to use e.g. log(3).
-AC_SEARCH_LIBS([log], [m], , [AC_MSG_ERROR([Missing math functions])])
-if test "x$ac_cv_search_log" != "xnone required" ; then
-  LM="$ac_cv_search_log"
-else
+
+# On MSVC, log is an intrinsic that doesn't require libm. However,
+# AC_SEARCH_LIBS does not successfully detect this, as it will try to compile
+# a program using the wrong signature for log. Newer versions of MSVC CL detects
+# this and rejects the program with the following messages.
+#
+# conftest.c(40): warning C4391: 'char log()': incorrect return type for intrinsic function, expected 'double'
+# conftest.c(44): error C2168: 'log': too few actual parameters for intrinsic function
+#
+# Since log is always available on MSVC (it's been around since the dawn of
+# time), we simply always assume it's there if MSVC is detected.
+if test "x$je_cv_msvc" = "xyes" ; then
   LM=
+else
+  AC_SEARCH_LIBS([log], [m], , [AC_MSG_ERROR([Missing math functions])])
+    if test "x$ac_cv_search_log" != "xnone required" ; then
+      LM="$ac_cv_search_log"
+    else
+      LM=
+    fi
 fi
 AC_SUBST(LM)