CI Add openSUSE with GCC 9.

.drone.yml

@@ -84,6 +84,24 @@ steps:
   - name: debian-package-cache
     path: /var/cache/apt/archives
 
+- name: GCC 9
+  image: opensuse/leap:15
+  pull: always
+  environment:
+    CXX: g++-9
+    CXXFLAGS: -pipe -O2
+    DEBIAN_FRONTEND: noninteractive
+    LANG: C.UTF-8
+  commands:
+  - find /etc/zypp/repos.d/ -type f -exec sed s/keeppackages=0/keeppackages=1/ {} \;
+  - zypper install cmake gcc9-c++ rpm-build
+  - zypper install catch2 libboost_program_options1_75_0-devel libboost_locale1_75_0-devel libboost_log1_75_0-devel fmt-devel libarchive-devel pugixml-devel nlohmann_json-devel asciidoc
+  - rm -rf build && mkdir -p build && cd build
+  - cmake -G "Unix Makefiles" -DWITH_TESTS=YES ..
+  - make VERBOSE=1
+  - make install DESTDIR=install
+  - ctest -V
+
 - name: notify
   image: drillster/drone-email
   pull: always

README.adoc

@@ -76,7 +76,7 @@ If you get the error message that `add-apt-repository` was not found, install
 ==== Dependencies
 
 * Tested OS: Linux
-* C\++ compiler with C++17 support (tested: link:{uri-gcc}[GCC] 8/10,
+* C\++ compiler with C++17 support (tested: link:{uri-gcc}[GCC] 8/9/10,
   link:{uri-clang}[clang] 6/11)
 * link:{uri-cmake}[CMake] (at least: 3.12)
 * link:{uri-boost}[Boost] (tested: 1.75.0 / 1.65.0)
@@ -107,6 +107,17 @@ sudo apt install build-essential cmake libboost-program-options-dev \
 [TIP]
 If `nlohmann-json-dev` can not be found, try `nlohmann-json3-dev`.
 
+===== Install dependencies in openSUSE
+
+[source,shell]
+--------------------------------------------------------------------------------
+sudo zypper install cmake gcc10-c++ rpm-build \
+                    libboost_program_options1_75_0-devel \
+                    libboost_locale1_75_0-devel libboost_log1_75_0-devel \
+                    fmt-devel libarchive-devel pugixml-devel \
+                    nlohmann_json-devel asciidoc
+--------------------------------------------------------------------------------
+
 ==== Get sourcecode
 
 ===== Release

cmake/packages.cmake

@@ -31,6 +31,9 @@ set(CPACK_DEBIAN_FILE_NAME
 # RPM
 set(CPACK_RPM_PACKAGE_LICENSE "AGPL-3")
 
+# Figure out dependencies automatically.
+set(CPACK_RPM_PACKAGE_AUTOREQ ON)
+
 # Should be set automatically, but it is not.
 execute_process(COMMAND uname -m
   OUTPUT_VARIABLE CPACK_RPM_PACKAGE_ARCHITECTURE