use system-wide pcre

SConstruct

@@ -49,6 +49,10 @@ def getThirdPartyShortNames():
         if not x.endswith( ".py" ) or x.find( "#" ) >= 0:
             continue
 
+        #use system-wide pcre
+        if x.find('pcre') >= 0:
+            continue
+
         lst.append( _rpartition( x, "." )[0] )
     return lst
 
@@ -523,9 +527,13 @@ elif "linux2" == os.sys.platform or "linux3" == os.sys.platform:
     linux = True
     platform = "linux"
 
+    # use system-wide pcre
+    env.Append( CPPPATH=["/usr/include"] )
+    env.Append( LIBS=["pcrecpp", "pcre"] )
+
     if os.uname()[4] == "x86_64" and not force32:
         linux64 = True
-        nixLibPrefix = "lib64"
+        nixLibPrefix = "lib"
         env.Append( LIBPATH=["/usr/lib64" , "/lib64" ] )
         env.Append( LIBS=["pthread"] )
 
@@ -704,6 +712,7 @@ if nix:
     # env.Append( " -Wconversion" ) TODO: this doesn't really work yet
     if linux:
         env.Append( CPPFLAGS=" -Werror " )
+        env.Append( CPPFLAGS=" -Wno-error=unused-but-set-variable -Wno-error=unused-but-set-parameter " ) # ignore new gcc 4.6 warnings
         if not has_option('clang'):
             env.Append( CPPFLAGS=" -fno-builtin-memcmp " ) # glibc's memcmp is faster than gcc's