From 1ea441c408673b5b507fb13e61e2bedba57cffca Mon Sep 17 00:00:00 2001
From: nightmareci <nightmareci@gmail.com>
Date: Sun, 15 Mar 2026 10:03:37 -0700
Subject: [PATCH] Fix fseeko/ftello/strcasecmp not being defined

---
 CMakeLists.txt | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index e60124ae..4ed3c5a4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -117,7 +117,23 @@ test_large_files(LARGE_FILES_SUPPORTED)
 if(LARGE_FILES_SUPPORTED)
     add_definitions(${LARGE_FILES_DEFINITIONS})
 endif()
-check_function_exists(fseeko HAVE_FSEEKO)
+check_c_source_compiles("
+  #define _POSIX_C_SOURCE 200112L
+  #include <stdio.h>
+  int main(int argc, char **argv) {
+    FILE *file = fopen(\"file\", \"r\");
+    int retval = !(fseeko(file, 0, SEEK_SET) >= 0 && ftello(file) >= 0);
+    fclose(file);
+    return retval;
+  }" HAVE_FSEEKO)
+if(HAVE_FSEEKO)
+  add_definitions(-D_POSIX_C_SOURCE=200112L)
+endif()
+
+if(NOT WIN32)
+  # Needed for strcasecmp
+  add_definitions(-D_DEFAULT_SOURCE)
+endif()
 
 if(NOT MSVC AND (CMAKE_COMPILER_IS_GNUCC OR CMAKE_C_COMPILER_ID MATCHES "Clang"))
     add_compile_options(-Wall)