[CI] Create an Appimage for 64bit builds (#570)

* [CI] Create AppImage file

* [CI] Updated Jenkinsfile

* [MISC] fix indentation

* [MISC] Fix indentation

* [MISC] Fix indentation

* [CI] 7z appimage and readme

Dockerfile

@@ -1,38 +1,46 @@
-
-
-FROM ubuntu:21.04 as build
+FROM ubuntu:20.04 as build
 
 ENV LANG C.UTF-8
 ARG DEBIAN_FRONTEND=noninteractive
 
-RUN dpkg --add-architecture i386 && \
-    apt-get update && \
-    apt-get upgrade -y && \
-    apt-get install -y \
-        binutils:i386 \
-        gcc-10:i386 \
-        g++-10:i386 \
-        python3.10 \
-        python \
-        make \
-        cmake \
-        git \
-        lld \
-        libsdl2-dev:i386 \
-        zlib1g-dev:i386 \
-        libbz2-dev:i386 \
-        libpng-dev:i386 \
-        libgles2-mesa-dev && \
-    ln -sf /usr/bin/python3.10 /usr/bin/python3 && \
-    ln -s /usr/bin/gcc-10 /usr/bin/gcc && \
-    ln -s /usr/bin/gcc-10 /usr/bin/cc && \
-    ln -s /usr/bin/g++-10 /usr/bin/g++ && \
-    ln -s /usr/bin/g++-10 /usr/bin/c++
-
+RUN apt-get update && \
+	apt-get upgrade -y && \
+	apt-get install -y \
+		binutils \
+		gcc-10 \
+		g++-10 \
+		p7zip-full \
+		python3.9 \
+		make \
+		cmake \
+		curl \
+		git \
+		lld \
+		libsdl2-dev \
+		zlib1g-dev \
+		libbz2-dev \
+		libpng-dev \
+		libgles2-mesa-dev && \    
+	ln -s /usr/bin/g++-10 /usr/bin/g++ && \
+	update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-10 10 && \
+	gcc --version && \
+	g++ --version
+	
+RUN apt-get clean autoclean && apt-get autoremove --yes && rm -rf /var/lib/apt /var/lib/cache /var/lib/log
+	
 RUN git clone https://github.com/Perlmint/glew-cmake.git && \
-    cmake glew-cmake && \
-    make -j$(nproc) && \
-    make install ARCH64=false
+	cmake glew-cmake && \
+	make -j$(nproc) && \
+	make install
+    
+ENV SDL2VER=2.0.22
+RUN curl -sLO https://libsdl.org/release/SDL2-${SDL2VER}.tar.gz && \
+	tar -xzf SDL2-${SDL2VER}.tar.gz && \
+	cd SDL2-${SDL2VER} && \
+	./configure --prefix=/usr && \
+	make && make install && \
+	rm ../SDL2-${SDL2VER}.tar.gz && \
+	cp -av /lib/libSDL* /lib/x86_64-linux-gnu/
 
 RUN mkdir /soh
 WORKDIR /soh