Refactor: moves memrchr to global impl for potential future use

CMakeLists.txt

@@ -1115,7 +1115,6 @@ elseif(SunOS)
         src/detection/displayserver/linux/xcb.c
         src/detection/displayserver/linux/xlib.c
         src/detection/font/font_linux.c
-        src/common/solaris/memrchr.c
         src/detection/gpu/gpu_sunos.c
         src/detection/gpu/gpu_pci.c
         src/detection/gtk_qt/gtk.c
@@ -1326,6 +1325,10 @@ endif()
 if(NOT WIN32)
     check_function_exists(pipe2 HAVE_PIPE2)
 endif()
+check_function_exists(memrchr HAVE_MEMRCHR)
+if(NOT HAVE_MEMRCHR)
+    list(APPEND LIBFASTFETCH_SRC src/common/impl/memrchr.c)
+endif()
 
 if(ENABLE_SYSTEM_YYJSON)
     find_package(yyjson)
@@ -1673,6 +1676,9 @@ if(ENABLE_LIBZFS)
         )
     endif()
 endif()
+if(NOT HAVE_MEMRCHR)
+    target_compile_definitions(libfastfetch PRIVATE FF_HAVE_CUSTOM_MEMRCHR=1)
+endif()
 
 if(LINUX)
     target_link_libraries(libfastfetch

src/common/impl/memrchr.c

@@ -0,0 +1,19 @@
+#include "common/memrchr.h"
+#include <stddef.h>
+#include <stdint.h>
+
+void* memrchr(const void* s, int c, size_t n)
+{
+    if (n == 0) return NULL;
+
+    const uint8_t uc = (uint8_t) c;
+
+    const uint8_t* p = (const uint8_t*) s + n;
+
+    while (n--)
+    {
+        if (*--p == uc) return (void*) p;
+    }
+
+    return NULL;
+}

src/common/memrchr.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// `memrchr` is a GNU extension and may not be declared by system headers even when the symbol exists.
+// Declare it unconditionally; the build system provides a fallback implementation when missing.
+void* memrchr(const void* s, int c, size_t n);
+
+#ifdef __cplusplus
+}
+#endif

src/common/solaris/memrchr.c

@@ -1,15 +0,0 @@
-#if defined(__sun) && ! defined(__illumos__)
-#include "memrchr.h"
-
-void *memrchr(const void *s, int c, size_t n)
-{
-    if(n == 0) return NULL;
-    const unsigned char *p = (const unsigned char *)s + n;
-    while (n--) {
-        if (*(--p) == (unsigned char) c)
-            return (void*) p;
-    }
-
-    return NULL;
-}
-#endif

src/common/solaris/memrchr.h

@@ -1,6 +0,0 @@
-#pragma once
-#include <stddef.h>
-
-#if defined(__sun) && !defined(__illumos__)
-void *memrchr(const void *s, int c, size_t n);
-#endif

src/detection/gpu/gpu_pci.c

@@ -1,6 +1,7 @@
 #include "gpu.h"
 #include "common/io.h"
 #include "common/properties.h"
+#include "common/memrchr.h"
 
 #include <stdlib.h>
 #ifdef __FreeBSD__
@@ -24,10 +25,6 @@
 #define FF_STR_INDIR(x) #x
 #define FF_STR(x) FF_STR_INDIR(x)
 
-#if defined(__sun) && ! defined(__illumos__)
-#include "common/solaris/memrchr.h"
-#endif
-
 static const FFstrbuf* loadPciIds()
 {
     static FFstrbuf pciids;