games/libretro-beetle_psx: Fix build on armv7

The functions __addsf3 and __adddf3 are part of libgcc which is not
provided when compiling with clang.  Fiddle with some #if directives to
provide shims if we compile with clang.

PR:		268077
MFH:		2022Q4 (build fix)

games/libretro-beetle_psx/Makefile

@@ -1,6 +1,6 @@
 PORTNAME=	libretro-beetle_psx
 PORTVERSION=	0.20220211
-PORTREVISION=	1
+PORTREVISION=	2
 CATEGORIES=	games
 
 MAINTAINER=	ports@FreeBSD.org
@@ -20,8 +20,14 @@ GH_TAGNAME=	88929ae
 
 PLIST_FILES=	lib/libretro/mednafen_psx_libretro.so
 
+.include <bsd.port.pre.mk>
+
+.if ${ARCH:Marmv?}
+USE_GCC=	yes:build
+.endif
+
 do-install:
 	${MKDIR} ${STAGEDIR}/${PREFIX}/lib/libretro;
 	${INSTALL_LIB} ${WRKSRC}/mednafen_psx_libretro.so ${STAGEDIR}/${PREFIX}/lib/libretro;
 
-.include <bsd.port.mk>
+.include <bsd.port.post.mk>

games/libretro-beetle_psx/files/patch-deps_lightning_lib_jit__arm-swf.c

@@ -0,0 +1,20 @@
+--- deps/lightning/lib/jit_arm-swf.c.orig	2022-11-30 10:43:45 UTC
++++ deps/lightning/lib/jit_arm-swf.c
+@@ -402,7 +402,7 @@ static void _swf_vaarg_d(jit_state_t*, jit_int32_t, ji
+ 	    BICI(rt, rn, encode_arm_immediate(im));			\
+     } while (0)
+ 
+-#if !defined(__GNUC__)
++#if !defined(__GNUC__) || defined(__llvm__)
+ float __addsf3(float u, float v)
+ {
+     return (u + v);
+@@ -414,6 +414,8 @@ __adddf3(double u, double v)
+     return (u + v);
+ }
+ 
++#endif
++#if !defined(__GNUC__)
+ float
+ __aeabi_fsub(float u, float v)
+ {