prog/tests: Fix MSVC build.

progs/tests/crossbar.c

@@ -145,7 +145,7 @@ static void Init( void )
 {
    const char * const ver_string = (const char * const)
        glGetString( GL_VERSION );
-   float ver = strtof( ver_string, NULL );
+   float ver = strtod( ver_string, NULL );
    GLint tex_units;
    GLint temp[ 256 ];