Add libsrt and openssl

[rtgoodwin]

Take what you will, etc. :)

• Add OpenSSL (though TBH there may be a bit of magic there...) - instructions from https://cutecoder.org/programming/compile-open-ssl-apple-silicon/ (note the commenter using 1.1.1i specifically, and does require Xcode installed)
  • but remove the dylibs which seem to want to get linked...
• Add SRT (new, high resilience/performance streaming protocol. Compiled into OBS, for example)
• typo on libass (disable-shread vs shared), resulting in dylink
• a couple of misc statement moves because apparently my bash is a bit weak :) gettext always seemed to be rebuilding for some reason too...

Output of linked library check:

otool -L ./ffmpeg
./ffmpeg:
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 904.4.0)
	/System/Library/Frameworks/CoreText.framework/Versions/A/CoreText (compatibility version 1.0.0, current version 1.0.0)
	/System/Library/Frameworks/VideoToolbox.framework/Versions/A/VideoToolbox (compatibility version 1.0.0, current version 1.0.0)
	/System/Library/Frameworks/Foundation.framework/Versions/C/Foundation (compatibility version 300.0.0, current version 1770.255.0)
	/System/Library/Frameworks/AudioToolbox.framework/Versions/A/AudioToolbox (compatibility version 1.0.0, current version 1000.0.0)
	/System/Library/Frameworks/CoreAudio.framework/Versions/A/CoreAudio (compatibility version 1.0.0, current version 1.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1292.60.1)
	/System/Library/Frameworks/AVFoundation.framework/Versions/A/AVFoundation (compatibility version 1.0.0, current version 2.0.0)
	/System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo (compatibility version 1.2.0, current version 1.5.0)
	/System/Library/Frameworks/CoreMedia.framework/Versions/A/CoreMedia (compatibility version 1.0.0, current version 1.0.0)
	/System/Library/Frameworks/CoreGraphics.framework/Versions/A/CoreGraphics (compatibility version 64.0.0, current version 1463.2.1)
	/System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL (compatibility version 1.0.0, current version 1.0.0)
	/usr/lib/libbz2.1.0.dylib (compatibility version 1.0.0, current version 1.0.5)
	/usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.11)
	/System/Library/Frameworks/CoreImage.framework/Versions/A/CoreImage (compatibility version 1.0.1, current version 5.0.0)
	/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit (compatibility version 45.0.0, current version 2022.20.117)
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1770.255.0)
	/System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices (compatibility version 1.0.0, current version 1122.11.0)
	/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)

[lindig]

I would like to see the fix for libass merged because otherwise the ffmpeg binary depends on a dynamically linked file that one would normally remove. Maybe propose this as an independent pull request?

diff --git a/build.bash b/build.bash
index 9ce8509..19cff03 100755
--- a/build.bash
+++ b/build.bash
@@ -353,7 +353,7 @@ function build_ass () {
     cd ${CMPLD}
     cd libass-0.15.0
     autoreconf -i
-    ./configure --prefix=${SRC} --disable-dependency-tracking --disable-shread --enable-static
+    ./configure --prefix=${SRC} --disable-dependency-tracking --disable-shared --enable-static
     make -j ${NUM_PARALLEL_BUILDS}
     make install
   fi