options: move bool value getter into cpp

Keeping the bool valueoption getter in the header was causing duplicate
definitions in the built static library.

options.cpp

@@ -127,6 +127,26 @@ presentoption::execute (void) {
 }
 
 
+/*
+ * Value option
+ */
+
+namespace util {
+    template<>
+    bool&
+    valueoption<bool>::get_arg(const std::string& arg, bool *val) {
+        if      (arg == "true"  || arg == "yes" || arg == "1")
+            *val = true;
+        else if (arg == "false" || arg == "no"  || arg == "0")
+            *val = false;
+        else
+            throw std::domain_error("Invalid form for boolean argument");
+
+        return *val;
+    }
+}
+
+
 /*
  * bytesoption
  */

options.hpp

@@ -192,23 +192,6 @@ namespace util {
     };
 
 
-    // God-damn Solaris strikes again with its antiquated everything. So you
-    // don't get these goodies on that system, with its ancient compiler.
-#if __GNUC__ >= 4
-    template<>
-    bool& valueoption<bool>::get_arg(const std::string& arg, bool * val) {
-        if      (arg == "true"  || arg == "yes" || arg == "1")
-            *val = true;
-        else if (arg == "false" || arg == "no"  || arg == "0")
-            *val = false;
-        else
-            throw std::domain_error("Invalid form for boolean argument");
-        
-        return *val;
-    }
-#endif
-
-
     /**
      * Interpret a (possibly) numeric value as a data size.
      *