Merge bitcoin#17663: build: pass -dead_strip_dylibs to ld on macOS

bd44711 build: pass -dead_strip_dylibs to ld on macOS (fanquake)

Pull request description:

  This strips some unused dylibs from bitcoin-qt.

  ```diff
  otool -L src/qt/bitcoin-qt
    /usr/lib/libSystem.B.dylib
  - /System/Library/Frameworks/DiskArbitration.framework/Versions/A/DiskArbitration
    /System/Library/Frameworks/IOKit.framework/Versions/A/IOKit
    /System/Library/Frameworks/Foundation.framework/Versions/C/Foundation
    /System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices
    /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit
    /System/Library/Frameworks/ApplicationServices.framework/Versions/A/ApplicationServices
    /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation
  -/System/Library/Frameworks/Security.framework/Versions/A/Security
    /System/Library/Frameworks/SystemConfiguration.framework/Versions/A/SystemConfiguration
    /System/Library/Frameworks/CoreGraphics.framework/Versions/A/CoreGraphics
    /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL
  -/System/Library/Frameworks/AGL.framework/Versions/A/AGL
    /System/Library/Frameworks/Carbon.framework/Versions/A/Carbon
    /usr/lib/libc++.1.dylib
    /System/Library/Frameworks/CFNetwork.framework/Versions/A/CFNetwork
    /System/Library/Frameworks/CoreText.framework/Versions/A/CoreText
    /System/Library/Frameworks/ImageIO.framework/Versions/A/ImageIO
    /usr/lib/libobjc.A.dylib
  ```

  `AGL` - ObjC wrapper for OpenGL.
  `DiskArbitration` - mount/unmount notifications and events.
  `Security` - low level security operations, authentication services.

  From `man ld`:
  ```
  Remove dylibs that are unreachable by the entry point or exported symbols.
  That is, suppresses the generation of load command commands for dylibs
  which supplied no symbols during the link. This option should not be
  used when linking against a dylib which is required at runtime for
  some indirect reason such as the dylib has an important initializer.
  ```

ACKs for top commit:
  theuni:
    ACK bd44711.

Tree-SHA512: 9592ce2966d28cb6c58e01efd401f56a4baa5dc5be5313f4fe8454632b578608be65a23c8602772049cd4655a9cb020fdd40d6622a244c301920d8c3db43f99a

configure.ac

@@ -783,6 +783,7 @@ fi
 dnl this flag screws up non-darwin gcc even when the check fails. special-case it.
 if test x$TARGET_OS = xdarwin; then
   AX_CHECK_LINK_FLAG([[-Wl,-dead_strip]], [LDFLAGS="$LDFLAGS -Wl,-dead_strip"])
+  AX_CHECK_LINK_FLAG([[-Wl,-dead_strip_dylibs]], [LDFLAGS="$LDFLAGS -Wl,-dead_strip_dylibs"])
 fi
 
 AC_CHECK_HEADERS([endian.h sys/endian.h byteswap.h stdio.h stdlib.h unistd.h strings.h sys/types.h sys/stat.h sys/select.h sys/prctl.h sys/sysctl.h vm/vm_param.h sys/vmmeter.h sys/resources.h])