diff --git a/src/core/stdc/fenv.d b/src/core/stdc/fenv.d
index 53befc976e2..e49aeaadba9 100644
--- a/src/core/stdc/fenv.d
+++ b/src/core/stdc/fenv.d
@@ -84,7 +84,7 @@ else version ( FreeBSD )
 }
 else
 {
-    static assert( false );
+    static assert( false, "Unsupported platform" );
 }
 
 enum
@@ -123,7 +123,7 @@ else version( FreeBSD )
 }
 else
 {
-    static assert( false );
+    static assert( false, "Unsupported platform" );
 }
 
 void feraiseexcept(int excepts);
diff --git a/src/core/stdc/stdarg.d b/src/core/stdc/stdarg.d
index 161aa4f9a59..97a02ac2c86 100644
--- a/src/core/stdc/stdarg.d
+++ b/src/core/stdc/stdarg.d
@@ -225,12 +225,12 @@ else version (X86_64)
             }
             else
             {
-                static assert(0);
+                static assert(false);
             }
         }
         else
         {
-            static assert(0, "not a valid argument type for va_arg");
+            static assert(false, "not a valid argument type for va_arg");
         }
     }
 
@@ -320,7 +320,7 @@ else version (X86_64)
         }
         else
         {
-            assert(0, "not a valid argument type for va_arg");
+            assert(false, "not a valid argument type for va_arg");
         }
     }
 
@@ -335,5 +335,5 @@ else version (X86_64)
 }
 else
 {
-    static assert(0, "Unsupported platform");
+    static assert(false, "Unsupported platform");
 }
diff --git a/src/core/stdc/stdio.d b/src/core/stdc/stdio.d
index caeafdeb0cd..b83ec2f9db0 100644
--- a/src/core/stdc/stdio.d
+++ b/src/core/stdc/stdio.d
@@ -110,7 +110,7 @@ else version ( FreeBSD )
 }
 else
 {
-    static assert( false );
+    static assert( false, "Unsupported platform" );
 }
 
 enum
@@ -221,7 +221,7 @@ struct _iobuf
     }
     else
     {
-        static assert( false );
+        static assert( false, "Unsupported platform" );
     }
 }
 
@@ -319,7 +319,7 @@ else version( FreeBSD )
 }
 else
 {
-    static assert( false );
+    static assert( false, "Unsupported platform" );
 }
 
 alias int fpos_t;
@@ -428,7 +428,7 @@ else version( FreeBSD )
 }
 else
 {
-    static assert( false );
+    static assert( false, "Unsupported platform" );
 }
 
 void perror(in char* s);
diff --git a/src/core/stdc/stdlib.d b/src/core/stdc/stdlib.d
index 514bbb879cd..73d136632bd 100644
--- a/src/core/stdc/stdlib.d
+++ b/src/core/stdc/stdlib.d
@@ -42,8 +42,12 @@ enum EXIT_SUCCESS = 0;
 enum EXIT_FAILURE = 1;
 enum MB_CUR_MAX   = 1;
 
-version(Windows)    enum RAND_MAX = 0x7fff;
-else version(Posix) enum RAND_MAX = 0x7fffffff;
+version(Windows)      enum RAND_MAX = 0x7fff;
+else version(linux)   enum RAND_MAX = 0x7fffffff;
+else version(OSX)     enum RAND_MAX = 0x7fffffff;
+else version(FreeBSD) enum RAND_MAX = 0x7fffffff;
+else version(Solaris) enum RAND_MAX = 0x7fff;
+else static assert( false, "Unsupported platform" );
 
 double  atof(in char* nptr);
 int     atoi(in char* nptr);