gcc backend: pass '-Wno-format' to gcc backend

- pass '-Wno-format' to prevent format string errors in gcc 9.x (enabled by default with -Wall)

(cherry picked from commit eaa67f5)

Author: jayrm

changelog.txt

@@ -14,6 +14,7 @@ Version 1.07.1
 
 [fixed]
 - makefile: under MSYS2 (and friends), TARGET_ARCH is now identified from shell's default target architecture instead of shell's host architecture
+- gcc backend: pass '-Wno-format' to prevent format string errors in gcc 9.x (enabled by default with -Wall)
 
 
 Version 1.07.0

src/compiler/fbc.bas

@@ -2939,6 +2939,13 @@ private function hCompileStage2Module( byval module as FBCIOFILE ptr ) as intege
 		'' Avoid gcc exception handling bloat
 		ln += "-fno-exceptions -fno-unwind-tables -fno-asynchronous-unwind-tables "
 
+		'' Prevent format string errors on gcc 9.x. (enabled by default with '-Wall')
+		'' TODO: fbc currently emits the ZSTRING type as 'uint8' when it
+		'' should probably preserve the 'char' type.  In C, there are 3 
+		'' distinct types, 'char', 'unsigned char', 'signed char'.
+		'' See ir-hlc.bas:hEmitType()
+		ln += "-Wno-format "
+
 		if( fbGetOption( FB_COMPOPT_DEBUGINFO ) ) then
 			ln += "-g "
 		end if