From 8773e8cef1c48f161b36b8ce2c402a940895729e Mon Sep 17 00:00:00 2001
From: Seth Kingsley <sethk@meowfishies.com>
Date: Wed, 12 Feb 2025 16:59:56 -0800
Subject: [PATCH] Just #define _GNU_SOURCE and _USE_MATH_MACROS unconditionally

Remove definitions of M_PI from source.
- _USE_MATH_MACROS is required by MSVC when compiling against UCRT.
- _GNU_SOURCE is required for other functions that are extensions to

The macros in math.h are not part of POSIX, but are visible by default
so long as you don't declare you are trying to be strictly
POSIX-conformant by defining _POSIX_C_SOURCE or _XOPEN_SOURCE.

Tested on:

- macOS 11.7.9 (it's old, sorry)
  Apple clang version 13.0.0,
  x86_64-apple-darwin20.6.0

- FreeBSD 14.2-RELEASE
  FreeBSD clang version 18.1.6
  x86_64-unknown-freebsd14.2

- Amazon Linux release 2 (Karoo) 4.14.336-253.554.amzn2.x86_64
  cc (GCC) 7.3.1 20180712 (Red Hat 7.3.1-17)
  x86_64-redhat-linux

- Windows 11 24H2:
  - MSYS2 c++ (GCC) 13.3.0
    x86_64-pc-msys
    msys-2.0.dll runtime

  - CLANG64 clang version 19.1.4
    x86_64-w64-windows-gnu
    ucrtbase.dll runtime

  - MINGW64 cc.exe (Rev2, Built by MSYS2 project) 14.2.0
    x86_64-w64-mingw32
    msvcrt.dll runtime

  - UCRT64 cc.exe (Rev2, Built by MSYS2 project) 14.2.0
    x86_64-w64-mingw32
    ucrtbase.dll runtime

  - Microsoft (R) C/C++ Optimizing Compiler Version 19.42.34433 for x64
    (Requires a few additional PRs that I will submit)
---
 libvmaf/meson.build                | 10 ++--------
 libvmaf/src/feature/adm_tools.c    |  4 ----
 libvmaf/src/feature/adm_tools.h    |  4 ----
 libvmaf/src/feature/integer_adm.h  |  4 ----
 libvmaf/src/feature/integer_ssim.c |  4 ----
 5 files changed, 2 insertions(+), 24 deletions(-)

diff --git a/libvmaf/meson.build b/libvmaf/meson.build
index cf20cecbd..a19893715 100644
--- a/libvmaf/meson.build
+++ b/libvmaf/meson.build
@@ -19,14 +19,8 @@ cc = meson.get_compiler('c')
 libvmaf_inc = include_directories(['include'])
 
 # Arguments in test_args will be used even on feature tests
-test_args = []
-if host_machine.system() == 'linux' or host_machine.system() == 'windows' or host_machine.system() == 'cygwin'
-    test_args += '-D_GNU_SOURCE'
-    add_project_arguments('-D_GNU_SOURCE', language: ['c', 'cpp'])
-elif host_machine.system() == 'darwin'
-    test_args += '-D_DARWIN_C_SOURCE'
-    add_project_arguments('-D_DARWIN_C_SOURCE', language: ['c', 'cpp'])
-endif
+test_args = ['-D_GNU_SOURCE', '-D_USE_MATH_DEFINES']
+add_project_arguments(test_args, language: ['c', 'cpp'])
 
 # Header checks
 stdatomic_dependency = []
diff --git a/libvmaf/src/feature/adm_tools.c b/libvmaf/src/feature/adm_tools.c
index 5278824e1..38925f4c4 100644
--- a/libvmaf/src/feature/adm_tools.c
+++ b/libvmaf/src/feature/adm_tools.c
@@ -28,10 +28,6 @@
 #include "adm_options.h"
 #include "adm_tools.h"
 
-#ifndef M_PI
-#define M_PI 3.1415926535897932384626433832795028841971693993751
-#endif
-
 #define MIN(x, y) (((x) < (y)) ? (x) : (y))
 #define MAX(x, y) (((x) > (y)) ? (x) : (y))
 
diff --git a/libvmaf/src/feature/adm_tools.h b/libvmaf/src/feature/adm_tools.h
index 184d9ca04..af1c218c5 100644
--- a/libvmaf/src/feature/adm_tools.h
+++ b/libvmaf/src/feature/adm_tools.h
@@ -19,10 +19,6 @@
 #include <math.h>
 #include "common/macros.h"
 
-#ifndef M_PI
-#define M_PI 3.14159265358979323846264338327
-#endif
-
 #pragma once
 
 #ifndef ADM_TOOLS_H_
diff --git a/libvmaf/src/feature/integer_adm.h b/libvmaf/src/feature/integer_adm.h
index bf3836460..876d48bf9 100644
--- a/libvmaf/src/feature/integer_adm.h
+++ b/libvmaf/src/feature/integer_adm.h
@@ -60,10 +60,6 @@ typedef struct AdmBuffer {
 #define NUM_BUFS_ADM 30
 #endif
 
-#ifndef M_PI
-#define M_PI 3.14159265358979323846264338327
-#endif // M_PI
-
 /* Enhancement gain imposed on adm, must be >= 1.0, where 1.0 means the gain is completely disabled */
 #ifndef DEFAULT_ADM_ENHN_GAIN_LIMIT
 #define DEFAULT_ADM_ENHN_GAIN_LIMIT (100.0)
diff --git a/libvmaf/src/feature/integer_ssim.c b/libvmaf/src/feature/integer_ssim.c
index 418b71f71..f5bc5fe54 100644
--- a/libvmaf/src/feature/integer_ssim.c
+++ b/libvmaf/src/feature/integer_ssim.c
@@ -35,10 +35,6 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define KERNEL_WEIGHT (1<<KERNEL_SHIFT)
 #define KERNEL_ROUND ((1<<KERNEL_SHIFT)>>1)
 
-#ifndef M_PI
-#define M_PI 3.141592653589793238462643
-#endif
-
 static int gaussian_filter_init(unsigned **_kernel,double _sigma,int _max_len){
   unsigned *kernel;
   double    scale;