Issue 355 -- Fixing docker image creation

Dockerfile

@@ -5,40 +5,48 @@ FROM gcc:9.5.0
 # Set up WORKDIR
 WORKDIR /usr/local/specfempp
 
-COPY . .
+ENV SOURCE=/usr/local/specfempp/source
+ENV BUILD=/usr/local/specfempp/build
 
-# Install CMake
+COPY . ${SOURCE}
+
+# Build and Install CMake
 RUN echo "Installing CMake..." && \
     echo "====================" && \
     echo "" && \
     apt-get update && \
-    apt-get install -y cmake && \
+    apt purge cmake && \
+    version=3.26 && \
+    build=5 && \
+    ## don't modify from here
+    mkdir ~/temp && \
+    cd ~/temp && \
+    wget https://cmake.org/files/v$version/cmake-$version.$build.tar.gz && \
+    tar -xzvf cmake-$version.$build.tar.gz && \
+    cd cmake-$version.$build/ && \
+    ./bootstrap --parallel=$(nproc) && \
+    make -j$(nproc) && \
+    make -j$(nproc) install && \
+    rm -rf ~/temp && \
     echo "Done."
 
 RUN echo "cmake version:" && \
     cmake --version && \
     echo "Done."
 
-# Install Boost
-RUN echo "Installing Boost..." && \
-    echo "====================" && \
-    echo "" && \
-    wget https://archives.boost.io/release/1.73.0/source/boost_1_73_0.tar.bz2 && \
-    tar --bzip2 -xf boost_1_73_0.tar.bz2 && \
-    cd boost_1_73_0 && \
-    ./bootstrap.sh --prefix=/usr/local/boost_1_73_0 && \
-    ./b2 install
-
 # Install SPECFEM++
 RUN echo "Installing SPECFEM++..." && \
     echo "========================" && \
     echo "" && \
+    cd ${SOURCE} && \
     git submodule init && git submodule update && \
-    cmake -S . -B build -D CMAKE_BUILD_TYPE=Release -D BUILD_TESTS=ON -D BUILD_EXAMPLES=ON && \
-    cmake --build build && \
+    rm -rf ${BUILD} && \
+    cmake -S ${SOURCE} -B ${BUILD} -D CMAKE_BUILD_TYPE=Release -D BUILD_TESTS=ON -D BUILD_EXAMPLES=ON && \
+    cmake --build ${BUILD} && \
+    rm -rf ${SOURCE} && \
     echo "Done."
 
 # Set environment variables
-ENV PATH="/usr/local/specfempp/build:${PATH}"
+ENV PATH="${BUILD}/bin:${PATH}"
 
 CMD ["/bin/bash"]