LuaJIT: don't apply ppc64 patchset for ppc (breaks JIT)

There is something in the ppc64 patch that breaks 32-bit ppc in
some scenarios (it appears to work but segfaults e.g. when
building neovim). So until that is investigated and fixed,
conditionalize this.

srcpkgs/LuaJIT/files/patches/ppc/musl-ppc-secureplt.patch

@@ -33,8 +33,6 @@ This fixes crashes on ppc-musl, as musl only supports secureplt.
  }
  
  #if LJ_HASJIT
-diff --git a/src/lj_dispatch.h b/src/lj_dispatch.h
-index 5bda51a..23f937f 100644
 --- src/lj_dispatch.h
 +++ src/lj_dispatch.h
 @@ -66,6 +66,21 @@ GOTDEF(GOTENUM)
@@ -68,14 +66,12 @@ index 5bda51a..23f937f 100644
    ASMFunction got[LJ_GOT__MAX];		/* Global offset table. */
  #endif
  #if LJ_HASJIT
-diff --git a/src/vm_ppc.dasc b/src/vm_ppc.dasc
-index 14a35d2..c239006 100644
 --- src/vm_ppc.dasc
 +++ src/vm_ppc.dasc
-@@ -51,7 +51,12 @@
+@@ -59,7 +59,12 @@
- |.macro blex, target; bl extern target; nop; .endmacro
+ |.define ENV_OFS,	8
- |.macro .toc, a, b; a, b; .endmacro
+ |.endif
- |.else
+ |.else  // No TOC.
 -|.macro blex, target; bl extern target@plt; .endmacro
 +|.macro blex, target
 +|  lwz TMP0, DISPATCH_GOT(target)(DISPATCH)
@@ -85,8 +81,8 @@ index 14a35d2..c239006 100644
 +|.endmacro
  |.macro .toc, a, b; .endmacro
  |.endif
- |.if OPD
+ |.macro .tocenv, a, b; .if TOCENV; a, b; .endif; .endmacro
-@@ -540,6 +545,8 @@
+@@ -448,6 +453,8 @@
  |// Assumes DISPATCH is relative to GL.
  #define DISPATCH_GL(field)	(GG_DISP2G + (int)offsetof(global_State, field))
  #define DISPATCH_J(field)	(GG_DISP2J + (int)offsetof(jit_State, field))

srcpkgs/LuaJIT/template

@@ -47,6 +47,23 @@ if [ "$CROSS_BUILD" ]; then
 	esac
 fi
 
+# the ppc64 patchset subtly breaks ppc, needs investigation; for
+# now apply patches conditionally, separately for ppc64 and ppc
+post_patch() {
+	local patchdir
+
+	case "$XBPS_TARGET_MACHINE" in
+		ppc64*) patchdir="ppc64";;
+		ppc*) patchdir="ppc";;
+		*) return;;
+	esac
+
+	for i in ${FILESDIR}/patches/${patchdir}/*.patch; do
+		msg_normal "patching: $i\n"
+		patch -sNp0 -i ${i}
+	done
+}
+
 do_build() {
 	local _cflags=$CFLAGS
 	local _ldflags=$LDFLAGS