fbc: thiscall, add the '-z nothiscall' option

- when '-z nothiscall' option is specified, fbc will not use 'thiscall' calling convention.

Author: jayrm

src/compiler/fb.bas

@@ -623,6 +623,8 @@ sub fbSetOption( byval opt as integer, byval value as integer )
 		env.clopt.gosubsetjmp = value
 	case FB_COMPOPT_VALISTASPTR
 		env.clopt.valistasptr = value
+	case FB_COMPOPT_NOTHISCALL
+		env.clopt.nothiscall = value
 	case FB_COMPOPT_EXPORT
 		env.clopt.export = value
 	case FB_COMPOPT_MSBITFIELDS
@@ -719,6 +721,8 @@ function fbGetOption( byval opt as integer ) as integer
 		function = env.clopt.gosubsetjmp
 	case FB_COMPOPT_VALISTASPTR
 		function = env.clopt.valistasptr
+	case FB_COMPOPT_NOTHISCALL
+		function = env.clopt.valistasptr
 	case FB_COMPOPT_EXPORT
 		function = env.clopt.export
 	case FB_COMPOPT_MSBITFIELDS

src/compiler/fb.bi

@@ -96,6 +96,7 @@ enum FB_COMPOPT
 	'' the rest
 	FB_COMPOPT_GOSUBSETJMP          '' boolean: implement GOSUB using setjmp/longjump?
 	FB_COMPOPT_VALISTASPTR          '' boolean: implement CVA_* using pointer expressions only?
+	FB_COMPOPT_NOTHISCALL           '' boolean: don't use 'thiscall' calling convention?
 	FB_COMPOPT_EXPORT               '' boolean: export all symbols declared as EXPORT?
 	FB_COMPOPT_MSBITFIELDS          '' boolean: use M$'s bitfields packing?
 	FB_COMPOPT_MULTITHREADED        '' boolean: -mt
@@ -289,6 +290,7 @@ type FBCMMLINEOPT
 	'' the rest
 	gosubsetjmp     as integer              '' implement GOSUB using setjmp/longjump? (default = false)
 	valistasptr     as integer              '' implement CVA_* using pointer expressions only?
+	nothiscall      as integer              '' do not use thiscall calling convention (default = false)
 	export          as integer              '' export all symbols declared as EXPORT (default = true)
 	msbitfields     as integer              '' use M$'s bitfields packing
 	multithreaded   as integer              '' link against thread-safe runtime library (default = false)

src/compiler/fbc.bas

@@ -2035,6 +2035,8 @@ private sub handleOpt(byval optid as integer, byref arg as string)
 			fbSetOption( FB_COMPOPT_GOSUBSETJMP, TRUE )
 		case "valist-as-ptr"
 			fbSetOption( FB_COMPOPT_VALISTASPTR, TRUE )
+		case "no-thiscall"
+			fbSetOption( FB_COMPOPT_NOTHISCALL, TRUE )
 		case else
 			hFatalInvalidOption( arg )
 		end select

src/compiler/parser-proc.bas

@@ -526,7 +526,10 @@ function cProcCallingConv( byval default as FB_FUNCMODE ) as FB_FUNCMODE
 		lexSkipToken( LEXCHECK_POST_SUFFIX )
 
 	case FB_TK_THISCALL
-		function = FB_FUNCMODE_THISCALL
+		'' ignore thiscall if '-z no-thiscall' was given
+		if( env.clopt.nothiscall = FALSE ) then
+			function = FB_FUNCMODE_THISCALL
+		end if
 		lexSkipToken( )
 
 	case else