Add support for MinGW-w64 v7.0.0

I've diffed the relevant subtress (mingw-w64-crt/lib{32,64,-common}) of
v6 and v7 manually and hopefully caught most potential regressions
(MS functions newly overridden by MinGW implementations).

buildsdk.d

@@ -91,7 +91,10 @@ void sanitizeDef(string defFile)
         // ucrtbase.def:
         "_assert", "_cabs", "_fpreset", "_tzset",
         "ceil", "ceilf", "coshf", "fabs",
+        "feclearexcept", "fegetenv", "fegetexceptflag", "fegetround", "feholdexcept",
+        "fesetenv", "fesetexceptflag", "fesetround", "fetestexcept",
         "floor", "floorf", "modf", "modff",
+        "lgamma", "lgammaf", "lgammal",
         "sinhf", "sqrt", "sqrtf", "wcsnlen",
         // additional ones in msvcr100.def:
         "__report_gsfailure",
@@ -104,7 +107,7 @@ void sanitizeDef(string defFile)
         "_wassert",
         "acosf", "asinf", "atan2", "atan2f", "atanf",
         "btowc",
-        "cos", "cosf", "exp", "expf", "fmod", "fmodf", "ldexp",
+        "cos", "cosf", "exp", "expf", "fmod", "fmodf", "frexp", "ldexp",
         "longjmp",
         "llabs", "lldiv",
         "log", "log10f", "logf",
@@ -143,10 +146,13 @@ void sanitizeDef(string defFile)
         }
 
         // Un-hide functions overridden by the MinGW runtime.
-        foreach (name; overriddenMinGWFunctions)
+        if (line.endsWith(" DATA"))
         {
-            if (line.length == name.length + 5 && line.startsWith(name) && line.endsWith(" DATA"))
-                return name;
+            foreach (name; overriddenMinGWFunctions)
+            {
+                if (line.length == name.length + 5 && line.startsWith(name))
+                    return name;
+            }
         }
 
         // Don't export function 'atexit'; we have our own in msvc_atexit.c.
@@ -248,7 +254,7 @@ bool defWithStdcallMangling2implib(string defFile)
             line.startsWith("LIBRARY ") || line.startsWith("EXPORTS"))
             return line;
 
-        if (line.endsWith(" DATA"))
+        if (line.length > 5 && (line[$-5] == ' ' || line[$-5] == '\t') && line.endsWith("DATA"))
         {
             fields ~= line[0 .. $-5];
             return line;