Fix linking debug bzip2 (#6570)

ports/ffmpeg/CONTROL

@@ -1,5 +1,5 @@
 Source: ffmpeg
-Version: 4.1-4
+Version: 4.1-5
 Description: a library to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created.
   FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge. No matter if they were designed by some standards committee, the community or a corporation. It is also highly portable: FFmpeg compiles, runs, and passes our testing infrastructure FATE across Linux, Mac OS X, Microsoft Windows, the BSDs, Solaris, etc. under a wide variety of build environments, machine architectures, and configurations.
 
@@ -23,6 +23,10 @@ Feature: lzma
 Build-Depends: liblzma
 Description: lzma support in ffmpeg
 
+Feature: bzip2
+Build-Depends: bzip2
+Description: bzip2 support in ffmpeg
+
 Feature: x264
 Build-Depends: x264, ffmpeg[gpl]
 Description: x264 support in ffmpeg

ports/ffmpeg/fixed-debug-bzip2-link.patch

@@ -0,0 +1,33 @@
+diff -urN a/configure b/configure
+--- a/configure	2018-09-08 20:53:33.556275600 +0800
++++ b/configure	2018-09-08 20:55:46.238584400 +0800
+@@ -4753,6 +4753,8 @@
+ enable $subarch
+ enabled spic && enable_weak pic
+ 
++bzlib_name=bz2
++
+ # OS specific
+ case $target_os in
+     aix)
+@@ -4914,6 +4916,11 @@
+         objformat="win32"
+         ranlib=:
+         enable dos_paths
++        if [ -z "${extra_cflags##*-MDd*}" ] || [ -z "${extra_cflags##*-MTd*}" ]; then
++            bzlib_name=bz2d
++        else
++            bzlib_name=bz2
++        fi
+         ;;
+     cygwin*)
+         target_os=cygwin
+@@ -5734,7 +5741,7 @@
+     check_builtin sem_timedwait semaphore.h "sem_t *s; sem_init(s,0,0); sem_timedwait(s,0); sem_destroy(s)"
+ 
+ disabled  zlib || check_lib  zlib.h      zlibVersion    -lz    || disable  zlib
+-disabled bzlib || check_lib bzlib.h BZ2_bzlibVersion    -lbz2  || disable bzlib
++disabled bzlib || check_lib bzlib.h BZ2_bzlibVersion    -l$bzlib_name  || disable bzlib
+ disabled  lzma || check_lib  lzma.h lzma_version_number -llzma || disable lzma
+ 
+ check_lib math.h sin -lm && LIBM="-lm"

ports/ffmpeg/portfile.cmake

@@ -16,6 +16,7 @@ vcpkg_extract_source_archive_ex(
         fix_windowsinclude-in-ffmpegexe-1.patch
         fix_windowsinclude-in-ffmpegexe-2.patch
         fix_windowsinclude-in-ffmpegexe-3.patch
+        fixed-debug-bzip2-link.patch
 )
 
 if (${SOURCE_PATH} MATCHES " ")
@@ -43,7 +44,6 @@ else()
 endif()
 
 set(ENV{INCLUDE} "${CURRENT_INSTALLED_DIR}/include;$ENV{INCLUDE}")
-set(ENV{LIB} "${CURRENT_INSTALLED_DIR}/lib;$ENV{LIB}")
 
 set(_csc_PROJECT_PATH ffmpeg)
 
@@ -102,12 +102,11 @@ else()
     set(OPTIONS "${OPTIONS} --disable-lzma")
 endif()
 
-# bzip2's debug library is named "bz2d", which isn't found by ffmpeg
-# if("bzip2" IN_LIST FEATURES)
-#     set(OPTIONS "${OPTIONS} --enable-bzip2")
-# else()
-#     set(OPTIONS "${OPTIONS} --disable-bzip2")
-# endif()
+if("bzip2" IN_LIST FEATURES)
+    set(OPTIONS "${OPTIONS} --enable-bzlib")
+else()
+    set(OPTIONS "${OPTIONS} --disable-bzlib")
+endif()
 
 if(VCPKG_CMAKE_SYSTEM_NAME STREQUAL "WindowsStore")
     set(ENV{LIBPATH} "$ENV{LIBPATH};$ENV{_WKITS10}references\\windows.foundation.foundationcontract\\2.0.0.0\\;$ENV{_WKITS10}references\\windows.foundation.universalapicontract\\3.0.0.0\\")
@@ -151,6 +150,9 @@ if(WIN32)
     endif()
 endif()
 
+set(ENV_LIB "$ENV{LIB}")
+
+set(ENV{LIB} "${CURRENT_INSTALLED_DIR}/lib;${ENV_LIB}")
 message(STATUS "Building ${_csc_PROJECT_PATH} for Release")
 file(MAKE_DIRECTORY ${CURRENT_BUILDTREES_DIR}/${TARGET_TRIPLET}-rel)
 vcpkg_execute_required_process(
@@ -163,6 +165,7 @@ vcpkg_execute_required_process(
     LOGNAME build-${TARGET_TRIPLET}-rel
 )
 
+set(ENV{LIB} "${CURRENT_INSTALLED_DIR}/debug/lib;${ENV_LIB}")
 message(STATUS "Building ${_csc_PROJECT_PATH} for Debug")
 file(MAKE_DIRECTORY ${CURRENT_BUILDTREES_DIR}/${TARGET_TRIPLET}-dbg)
 vcpkg_execute_required_process(