Try clang instead of gcc on mac, because of seemingly internal errors

like this:
/usr/include/c++/4.2.1/bits/localefwd.h:58:34: error: macro "isspace"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:70:34: error: macro "isupper"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:74:34: error: macro "islower"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:78:34: error: macro "isalpha"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:94:34: error: macro "isalnum"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:102:34: error: macro "toupper"
passed 2 arguments, but takes just 1
/usr/include/c++/4.2.1/bits/localefwd.h:106:34: error: macro "tolower"
passed 2 arguments, but takes just 1
In file included from /usr/include/c++/4.2.1/bits/basic_ios.h:44,