diff --git a/pkgs/mpich.sh b/pkgs/mpich.sh
index 3f16c50..2bf0f88 100644
--- a/pkgs/mpich.sh
+++ b/pkgs/mpich.sh
@@ -6,7 +6,7 @@ cleanup=""
 
 version=3.4
 pfile=mpich-${version}.tar.gz
-src=$(eval "@TOP_DIR@/tools/fetch_check.sh" http://www.mpich.org/static/downloads/${version}/${pfile} ${pfile})
+src=$(eval "@TOP_DIR@/tools/fetch_check.sh" https://www.mpich.org/static/downloads/${version}/${pfile} ${pfile})
 
 if [ "x${src}" = "x" ]; then
     echo "Failed to fetch ${pkg}" >&2
diff --git a/pkgs/zlib.sh b/pkgs/zlib.sh
index 2bba482..ea84bb7 100644
--- a/pkgs/zlib.sh
+++ b/pkgs/zlib.sh
@@ -4,9 +4,9 @@ pkg="zlib"
 pkgopts=$@
 cleanup=""
 
-version=1.2.11
+version=1.2.12
 pfile=zlib-${version}.tar.gz
-src=$(eval "@TOP_DIR@/tools/fetch_check.sh" http://zlib.net/${pfile} ${pfile})
+src=$(eval "@TOP_DIR@/tools/fetch_check.sh" https://zlib.net/${pfile} ${pfile})
 
 if [ "x${src}" = "x" ]; then
     echo "Failed to fetch ${pkg}" >&2
@@ -26,7 +26,7 @@ rm -rf zlib-${version}
 tar xzf ${src} \
     && cd zlib-${version} \
     && cleanup="${cleanup} $(pwd)" \
-    && CC="@BUILD_CC@" ./configure \
+    && CC="@BUILD_CC@" CFLAGS="-O3 -fPIC" ./configure \
     --shared --prefix="@AUX_PREFIX@" > ${log} 2>&1 \
     && make -j @MAKEJ@ >> ${log} 2>&1 \
     && make install >> ${log} 2>&1
diff --git a/tools/docker-entrypoint.sh b/tools/docker-entrypoint.sh
index 8578277..131355f 100755
--- a/tools/docker-entrypoint.sh
+++ b/tools/docker-entrypoint.sh
@@ -34,7 +34,11 @@ _is_sourced() {
 # Loads various settings that are used elsewhere in the script
 # This should be called before any other functions
 docker_setup_env() {
-    source cmbenv
+    # Our docker builds install to /usr/local, so this is
+    # not needed.  In fact, it can cause problems since the
+    # setup script will manipulate LD_LIBRARY_PATH.
+    #source cmbenv
+    echo "" > /dev/null
 }
 
 _main() {