msvc: handle DEVELOPER=1

We frequently build Git using the `DEVELOPER=1` make setting as a
shortcut to enable all kinds of more stringent compiler warnings.

Those compiler warnings are relatively specific to GCC, though, so let's
try our best to translate them to the equivalent options to pass to MS
Visual C++'s `cl.exe`.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

compat/vcbuild/scripts/clink.pl

@@ -70,6 +70,52 @@ while (@ARGV) {
 		push(@lflags, $arg);
 	} elsif ("$arg" =~ /^-[Rl]/) {
 		# eat
+	} elsif ("$arg" eq "-Werror") {
+		push(@cflags, "-WX");
+	} elsif ("$arg" eq "-Wall") {
+		# cl.exe understands -Wall, but it is really overzealous
+		push(@cflags, "-W4");
+		# disable the "signed/unsigned mismatch" warnings; our source code violates that
+		push(@cflags, "-wd4018");
+		push(@cflags, "-wd4245");
+		push(@cflags, "-wd4389");
+		# disable the "unreferenced formal parameter" warning; our source code violates that
+		push(@cflags, "-wd4100");
+		# disable the "conditional expression is constant" warning; our source code violates that
+		push(@cflags, "-wd4127");
+		# disable the "const object should be initialized" warning; these warnings affect only objects that are `static`
+		push(@cflags, "-wd4132");
+		# disable the "function/data pointer conversion in expression" warning; our source code violates that
+		push(@cflags, "-wd4152");
+		# disable the "non-constant aggregate initializer" warning; our source code violates that
+		push(@cflags, "-wd4204");
+		# disable the "cannot be initialized using address of automatic variable" warning; our source code violates that
+		push(@cflags, "-wd4221");
+		# disable the "possible loss of data" warnings; our source code violates that
+		push(@cflags, "-wd4244");
+		push(@cflags, "-wd4267");
+		# disable the "array is too small to include a terminating null character" warning; we ab-use strings to initialize OIDs
+		push(@cflags, "-wd4295");
+		# disable the "'<<': result of 32-bit shift implicitly converted to 64 bits" warning; our source code violates that
+		push(@cflags, "-wd4334");
+		# disable the "declaration hides previous local declaration" warning; our source code violates that
+		push(@cflags, "-wd4456");
+		# disable the "declaration hides function parameter" warning; our source code violates that
+		push(@cflags, "-wd4457");
+		# disable the "declaration hides global declaration" warning; our source code violates that
+		push(@cflags, "-wd4459");
+		# disable the "potentially uninitialized local variable '<name>' used" warning; our source code violates that
+		push(@cflags, "-wd4701");
+		# disable the "unreachable code" warning; our source code violates that
+		push(@cflags, "-wd4702");
+		# disable the "potentially uninitialized local pointer variable used" warning; our source code violates that
+		push(@cflags, "-wd4703");
+		# disable the "assignment within conditional expression" warning; our source code violates that
+		push(@cflags, "-wd4706");
+		# disable the "'inet_ntoa': Use inet_ntop() or InetNtop() instead" warning; our source code violates that
+		push(@cflags, "-wd4996");
+	} elsif ("$arg" =~ /^-W[a-z]/) {
+		# let's ignore those
 	} else {
 		push(@args, $arg);
 	}