Applying ./patches/010-matroska-memory-leak.patch using plaintext: 
patching file src/metadata/matroska_handler.cc

Applying ./patches/020-meson.patch using plaintext: 
patching file .gitignore
patching file meson.build
patching file meson_options.txt
patching file subprojects/.gitignore
patching file subprojects/fmt.wrap
patching file subprojects/gtest.wrap
patching file subprojects/lastfmlib.wrap
patching file subprojects/libebml.wrap
patching file subprojects/libexif.wrap
patching file subprojects/libffmpegthumbnailer.wrap
patching file subprojects/libmatroska.wrap
patching file subprojects/libnpupnp.wrap
patching file subprojects/libupnp.wrap
patching file subprojects/packagefiles/lastfmlib/meson.build
patching file subprojects/pugixml.wrap
patching file subprojects/spdlog.wrap
patching file subprojects/sqlite3.wrap
patching file subprojects/taglib.wrap
patching file test/config/meson.build
patching file test/content/meson.build
patching file test/core/meson.build
patching file test/database/meson.build
patching file test/meson.build
patching file test/scripting/meson.build
patching file test/util/meson.build
The Meson build system
Version: 0.61.5
Source dir: /mnt/immortalwrt-18.06/build_dir/target-mipsel_mips32_musl/gerbera-1.11.0
Build dir: /mnt/immortalwrt-18.06/build_dir/target-mipsel_mips32_musl/gerbera-1.11.0/openwrt-build
Build type: cross build
Project name: gerbera
Project version: 1.11.0
C compiler for the host machine: ccache_cc (gcc 8.4.0 "mipsel-openwrt-linux-musl-gcc (OpenWrt GCC 8.4.0 r8158-f4e2b7aa3) 8.4.0")
C linker for the host machine: ccache_cc ld.bfd 2.34
C++ compiler for the host machine: ccache_cxx (gcc 8.4.0 "mipsel-openwrt-linux-musl-g++ (OpenWrt GCC 8.4.0 r8158-f4e2b7aa3) 8.4.0")
C++ linker for the host machine: ccache_cxx ld.bfd 2.34
C compiler for the build machine: ccache gcc (gcc 8.4.0 "gcc (Ubuntu 8.4.0-3ubuntu2) 8.4.0")
C linker for the build machine: gcc ld.bfd 2.34
C++ compiler for the build machine: ccache g++ (gcc 8.4.0 "g++ (Ubuntu 8.4.0-3ubuntu2) 8.4.0")
C++ linker for the build machine: g++ ld.bfd 2.34
Build machine cpu family: x86_64
Build machine cpu: x86_64
Host machine cpu family: mips
Host machine cpu: generic
Target machine cpu family: mips
Target machine cpu: generic
Library stdc++fs found: YES
Found pkg-config: /mnt/immortalwrt-18.06/staging_dir/host/bin/pkg-config (1.8.0)
Run-time dependency fmt found: YES 8.1.1
Run-time dependency pugixml found: YES 1.12
Run-time dependency spdlog found: YES 1.9.2
Run-time dependency sqlite3 found: YES 3.37.0
Run-time dependency iconv found: YES
Checking if "built-in atomics" : links: NO 
Library atomic found: YES
Checking for function "nl_langinfo" : YES 
Checking for function "setlocale" : YES 
Run-time dependency uuid found: YES 2.37.4
Found CMake: /mnt/immortalwrt-18.06/staging_dir/host/bin/cmake (3.22.3)
Run-time dependency nsl found: NO (tried pkgconfig and cmake)
Run-time dependency socket found: NO (tried pkgconfig and cmake)
Run-time dependency libavcodec found: YES 59.18.100
Run-time dependency libavfilter found: NO (tried pkgconfig and cmake)

../../../../build_dir/target-mipsel_mips32_musl/gerbera-1.11.0/meson.build:89:0: ERROR: Dependency "libavfilter" not found, tried pkgconfig and cmake

A full log can be found at /mnt/immortalwrt-18.06/build_dir/target-mipsel_mips32_musl/gerbera-1.11.0/openwrt-build/meson-logs/meson-log.txt
make[2]: *** [Makefile:88: /mnt/immortalwrt-18.06/build_dir/target-mipsel_mips32_musl/gerbera-1.11.0/.configured_4f474fad45514f27d895d5757bdf8986] Error 1
time: package/feeds/packages/gerbera/compile#1.94#0.35#2.48