Renaming pt_BR to pt, as a recent reform [1] made most country speaking portugese use a same, common version of it, which we want to use here.

[1] http://www.reformaortografica.com/

source/blender/blenfont/intern/blf_lang.c

@@ -82,7 +82,7 @@ static const char *locales[] = {
 	"spanish", "es",
 	"catalan", "ca_AD",
 	"czech", "cs_CZ",
-	"ptb", "pt_BR",
+	"ptb", "pt",
 #if defined (_WIN32) && !defined(FREE_WINDOWS)
 	"Chinese (Simplified)_China.1252", "zh_CN",
 	"Chinese (Traditional)_China.1252", "zh_TW",

source/blender/makesrna/intern/rna_userdef.c

@@ -2869,7 +2869,7 @@ static void rna_def_userdef_system(BlenderRNA *brna)
 		{ 0, "", 0, "In progress", ""},
 		/* using the utf8 flipped form of Arabic (العربية) */
 		{21, "ARABIC", 0, "Arabic (ﺔﻴﺑﺮﻌﻟﺍ)", "ar_EG"},
-		{12, "BRAZILIAN_PORTUGUESE", 0, "Brazilian Portuguese (Português do Brasil)", "pt_BR"},
+		{12, "BRAZILIAN_PORTUGUESE", 0, "Portuguese (Português)", "pt"},
 		{22, "BULGARIAN", 0, "Bulgarian (Български)", "bg_BG"},
 		{10, "CATALAN", 0, "Catalan (Català)", "ca_AD"},
 		{16, "CROATIAN", 0, "Croatian (Hrvatski)", "hr_HR"},