SDL: Define illegal_instruction() when it will be actually used

From 29d21164951e5884c98bc8d817ffeceef76b00ff Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Thu, 8 May 2025 11:51:35 -0700
Subject: [PATCH] Define illegal_instruction() when it will be actually used

---
 src/cpuinfo/SDL_cpuinfo.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/cpuinfo/SDL_cpuinfo.c b/src/cpuinfo/SDL_cpuinfo.c
index a8feec846ff61..b836532800e3c 100644
--- a/src/cpuinfo/SDL_cpuinfo.c
+++ b/src/cpuinfo/SDL_cpuinfo.c
@@ -115,7 +115,11 @@
 #define CPU_CFG2_LSX  (1 << 6)
 #define CPU_CFG2_LASX (1 << 7)
 
-#if defined(SDL_ALTIVEC_BLITTERS) && defined(HAVE_SETJMP) && !defined(SDL_PLATFORM_MACOS) && !defined(SDL_PLATFORM_OPENBSD) && !defined(SDL_PLATFORM_FREEBSD) && (defined(SDL_PLATFORM_LINUX) && !defined(HAVE_GETAUXVAL))
+#if !defined(SDL_CPUINFO_DISABLED) && \
+    !((defined(SDL_PLATFORM_MACOS) && (defined(__ppc__) || defined(__ppc64__))) || (defined(SDL_PLATFORM_OPENBSD) && defined(__powerpc__))) && \
+    !(defined(SDL_PLATFORM_FREEBSD) && defined(__powerpc__)) && \
+    !(defined(SDL_PLATFORM_LINUX) && defined(__powerpc__) && defined(HAVE_GETAUXVAL)) && \
+    defined(SDL_ALTIVEC_BLITTERS) && defined(HAVE_SETJMP)
 /* This is the brute force way of detecting instruction sets...
    the idea is borrowed from the libmpeg2 library - thanks!
  */