Add code improvements for SUN OS compilation

https://gist.github.com/jperkin/4b88403da41f556e540d

Author: mgreter

configure.ac

@@ -13,10 +13,13 @@ AC_CONFIG_AUX_DIR([script])
 # Though they look like gcc flags!
 AM_INIT_AUTOMAKE([foreign parallel-tests -Wall])
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([no])])
+# would fail with mingw otherwise
+m4_pattern_allow([AM_PROG_AR])
 
 # Checks for programs.
 AC_PROG_CXX
 AC_LANG([C++])
+AM_PROG_AR([])
 LT_INIT([dlopen])
 
 # Checks for header files.

units.hpp

@@ -5,6 +5,10 @@
 #include <string>
 #include <sstream>
 
+#ifdef __sun
+#undef SEC
+#endif
+
 namespace Sass {
   using namespace std;
 
@@ -59,9 +63,9 @@ namespace Sass {
   extern const double frequency_conversion_factors[2][2];
   extern const double resolution_conversion_factors[3][3];
 
-  SassUnit string_to_unit(const string&);
+  enum SassUnit string_to_unit(const string&);
   const char* unit_to_string(SassUnit unit);
-  SassUnitType get_unit_type(SassUnit unit);
+  enum SassUnitType get_unit_type(SassUnit unit);
   // throws incompatibleUnits exceptions
   double conversion_factor(const string&, const string&);