configure: Separate commonalities in msvc and icl flags

Allows for easier handling of flags that may be specific to icl or msvc.
Furthermore, simplify the handling of warnings and remarks thanks to
icl's support of -Wall on Windows.

Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

configure

@@ -2340,16 +2340,17 @@ ccc_flags(){
    done
 }
 
-msvc_flags(){
+msvc_common_flags(){
     for flag; do
         case $flag in
+            # In addition to specifying certain flags under the compiler
+            # specific filters, they must be specified here as well or else the
+            # generic catch all at the bottom will print the original flag.
+            -Wall)                ;;
+            -std=c99)             ;;
+            # Common flags
             -fomit-frame-pointer) echo -Oy ;;
             -g)                   echo -Z7 ;;
-            -Wall)                echo -W4 -wd4244 -wd4127 -wd4018 -wd4389 \
-                                       -wd4146 -wd4057 -wd4204 -wd4706 -wd4305 \
-                                       -wd4152 -wd4324 -we4013 -wd4100 -wd4214 \
-                                       -wd4996 -wd4273 ;;
-            -std=c99)             ;;
             -fno-math-errno)      ;;
             -fno-common)          ;;
             -fno-signed-zeros)    ;;
@@ -2365,6 +2366,30 @@ msvc_flags(){
     done
 }
 
+msvc_flags(){
+    msvc_common_flags "$@"
+    for flag; do
+        case $flag in
+            -Wall)                echo -W4 -wd4244 -wd4127 -wd4018 -wd4389 \
+                                       -wd4146 -wd4057 -wd4204 -wd4706 -wd4305 \
+                                       -wd4152 -wd4324 -we4013 -wd4100 -wd4214 \
+                                       -wd4996 -wd4273 ;;
+        esac
+    done
+}
+
+icl_flags(){
+    msvc_common_flags "$@"
+    for flag; do
+        case $flag in
+            # Despite what Intel's documentation says -Wall, which is supported
+            # on Windows, does enable remarks so disable them here.
+            -Wall)                echo $flag -Qdiag-disable:remark ;;
+            -std=c99)             echo -Qstd=c99 ;;
+        esac
+    done
+}
+
 pgi_flags(){
     for flag; do
         case $flag in
@@ -2590,13 +2615,13 @@ probe_cc(){
         fi
         _cc_o='-Fo $@'
         _cc_e='-P'
-        _flags_filter=msvc_flags
+        _flags_filter=icl_flags
         _ld_lib='lib%.a'
         _ld_path='-libpath:'
         # -Qdiag-error to make icl error when presented with certain unknown arguments
         _flags='-nologo -Qdiag-error:10157 -Qdiag-error:4044'
         # -Qvec- -Qsimd- to prevent miscompilation, -GS for consistency with msvc which enables it by default
-        _cflags='-D_USE_MATH_DEFINES -Dinline=__inline -FIstdlib.h -Dstrtoll=_strtoi64 -Qstd=c99 -Qms0 -Qvec- -Qsimd- -GS'
+        _cflags='-D_USE_MATH_DEFINES -Dinline=__inline -FIstdlib.h -Dstrtoll=_strtoi64 -Qms0 -Qvec- -Qsimd- -GS'
         if [ $pfx = hostcc ]; then
             append _cflags -Dsnprintf=_snprintf
         fi
@@ -3916,7 +3941,6 @@ elif enabled msvc; then
     enabled x86_32 && disable aligned_stack
 elif enabled icl; then
     enabled x86_32 && disable aligned_stack
-    check_cflags -W1 # Just warnings, no remark spam
     # basically -fstrict-aliasing for icl that doesn't work (correctly) on 13.x+
     check_cpp_condition "windows.h" "__ICL < 1300" && add_cflags -Qansi-alias
     # icl will pass the inline asm tests but inline asm is currently not supported (build will fail)