Use a template for generating Dockerfiles

Since the firefox and chrome builds are similar except for the TLS
library used, it makes sense to unify their Dockerfiles. This commit
introduces a template Dockerfile from which both the build Dockerfiles
are generated using the simple 'mustache' template system.

firefox/Dockerfile

@@ -1,22 +1,34 @@
-# Python is needed for building libnss
+#
+# NOTE: THIS DOCKERFILE IS GENERATED FROM "Dockerfile.template" VIA
+# "generate-dockerfiles.sh".
+#
+# PLEASE DO NOT EDIT IT DIRECTLY.
+#
+
+# Python is needed for building libnss.
+# Use it as a common base.
 FROM python:3.10.1-slim-buster
 
 WORKDIR /build
 
+# Common dependencies
+RUN apt-get update && \
+    apt-get install -y git ninja-build cmake curl zlib1g-dev
+
 # Dependencies for building libnss
 # See https://firefox-source-docs.mozilla.org/security/nss/build.html#mozilla-projects-nss-building
-RUN apt-get update && \
-    apt-get install -y mercurial git ninja-build cmake python3-pip curl zlib1g-dev
-
-# The following are needed because we are going to change some autoconf scripts,
-# both for libnghttp2 and curl.
-RUN apt-get install -y autoconf automake autotools-dev pkg-config libtool
+RUN apt-get install -y mercurial python3-pip
 
 # curl tries to load the CA certificates for libnss.
 # It loads them from /usr/lib/x86_64-linux-gnu/nss/libnssckbi.so,
 # which is supplied by libnss3 on Debian/Ubuntu
 RUN apt-get install -y libnss3
 
+
+# The following are needed because we are going to change some autoconf scripts,
+# both for libnghttp2 and curl.
+RUN apt-get install -y autoconf automake autotools-dev pkg-config libtool
+
 # Download and compile libbrotli
 ARG BROTLI_VERSION=1.0.9
 RUN curl -L https://github.com/google/brotli/archive/refs/tags/v${BROTLI_VERSION}.tar.gz -o brotli-${BROTLI_VERSION}.tar.gz && \
@@ -33,12 +45,13 @@ ARG NSS_VERSION=nss-3.74
 # This tarball is already bundled with nspr, a dependency of libnss.
 ARG NSS_URL=https://ftp.mozilla.org/pub/security/nss/releases/NSS_3_74_RTM/src/nss-3.74-with-nspr-4.32.tar.gz
 
-# Download the nss library.
+# Download and compile nss.
 RUN curl -o ${NSS_VERSION}.tar.gz ${NSS_URL}
 RUN tar xf ${NSS_VERSION}.tar.gz && \
     cd ${NSS_VERSION}/nss && \
     ./build.sh -o --disable-tests --static
 
+
 ARG NGHTTP2_VERSION=nghttp2-1.46.0
 ARG NGHTTP2_URL=https://github.com/nghttp2/nghttp2/releases/download/v1.46.0/nghttp2-1.46.0.tar.bz2
 
@@ -68,13 +81,14 @@ RUN cd ${CURL_VERSION} && \
     for p in $(ls curl-*.patch); do patch -p1 < $p; done && \
     autoreconf -fi
 
-# Compile curl with nss
+# Compile curl with nghttp2, libbrotli and nss (firefox) or boringssl (chrome).
+# Enable keylogfile for debugging of TLS traffic.
 RUN cd ${CURL_VERSION} && \
     ./configure --enable-static \
                 --disable-shared \
-                --with-nss=/build/${NSS_VERSION}/dist/Release \
                 --with-nghttp2=/usr/local \
                 --with-brotli=/build/brotli-${BROTLI_VERSION}/build/installed \
+                --with-nss=/build/${NSS_VERSION}/dist/Release \
                 CFLAGS="-I/build/${NSS_VERSION}/dist/public/nss -I/build/${NSS_VERSION}/dist/Release/include/nspr" \
                 USE_CURL_SSLKEYLOGFILE=true && \
     make
@@ -85,9 +99,9 @@ RUN mkdir out && \
 
 # Re-compile libcurl dynamically
 RUN cd ${CURL_VERSION} && \
-    ./configure --with-nss=/build/${NSS_VERSION}/dist/Release \
-                --with-nghttp2=/usr/local \
+    ./configure --with-nghttp2=/usr/local \
                 --with-brotli=/build/brotli-${BROTLI_VERSION}/build/installed \
+                --with-nss=/build/${NSS_VERSION}/dist/Release \
                 CFLAGS="-I/build/${NSS_VERSION}/dist/public/nss -I/build/${NSS_VERSION}/dist/Release/include/nspr" \
                 USE_CURL_SSLKEYLOGFILE=true && \
     make clean && make
@@ -101,7 +115,6 @@ RUN ver=$(readlink -f curl-7.81.0/lib/.libs/libcurl.so | sed 's/.*so\.//') && \
     ln -s "libcurl-impersonate.so.$ver" "out/libcurl-impersonate.so" && \
     strip "out/libcurl-impersonate.so.$ver"
 
-
-# Wrapper script
+# Wrapper scripts
 COPY curl_ff* out/
 RUN chmod +x out/curl_*