install: add --additional-nginx-configure-arguments option (#1344)

Instead of requiring people to answer a prompt to specify which additional
arguments they would like nginx to be built with, allow people to specify
arguments like this on the command line.  The quoting is not ideal, since
it's important to pass spaces etc properly all the way through to the
underlying commands, but I give an example in the help text.

Fixes https://github.com/pagespeed/ngx_pagespeed/issues/1340

scripts/build_ngx_pagespeed.sh

@@ -80,6 +80,13 @@ Options:
       Assume the answer to all prompts is 'yes, please continue'.  Intended for
       automated usage, such as buildbots.
 
+  -a, --additional-nginx-configure-arguments
+      When running ./configure for nginx, you may want to specify additional
+      arguments, such as --with-http_ssl_module.  By default this script will
+      pause and prompt you for them, but this option lets you pass them in.  For
+      example, you might do:
+        -a '--with-http_ssl_module --with-cc-opt=\"-I /usr/local/include\"'
+
   -d, --dryrun
       Don't make any changes to the system, just print what changes you
       would have made.
@@ -302,10 +309,10 @@ function build_ngx_pagespeed() {
     fail "Your version of getopt is too old.  Exiting with no changes made."
   fi
 
-  opts=$(getopt -o v:n:mb:pslt:ydh \
+  opts=$(getopt -o v:n:mb:pslt:ya:dh \
     --longoptions ngx-pagespeed-version:,nginx-version:,dynamic-module \
     --longoptions buildir:,no-deps-check,psol-from-source,devel,build-type: \
-    --longoptions assume-yes,dryrun,help \
+    --longoptions assume-yes,additional-nginx-configure-arguments:,dryrun,help \
     -n "$(basename "$0")" -- "$@")
   if [ $? != 0 ]; then
     usage
@@ -356,6 +363,10 @@ function build_ngx_pagespeed() {
       -y | --assume-yes) shift
         ASSUME_YES="true"
         ;;
+      -a | --additional-nginx-configure-arguments) shift
+        ADDITIONAL_NGINX_CONFIGURE_ARGUMENTS="$1"
+        shift
+        ;;
       -d | --dryrun) shift
         DRYRUN="true"
         ;;
@@ -721,19 +732,26 @@ Not deleting $directory; name is suspiciously short.  Something is wrong."
     run cd "$nginx_dir"
 
     configure=("$configure_location/configure" "${configure_args[@]}")
+    additional_configure_args=""
+    if [ -z "${ADDITIONAL_NGINX_CONFIGURE_ARGUMENTS+x}" ]; then
       if ! "$ASSUME_YES"; then
         echo "About to build nginx.  Do you have any additional ./configure"
         echo "arguments you would like to set?  For example, if you would like"
         echo "to build nginx with https support give --with-http_ssl_module"
         echo "If you don't have any, just press enter."
         read -p "> " additional_configure_args
+      fi
+    else
+      additional_configure_args="$ADDITIONAL_NGINX_CONFIGURE_ARGUMENTS"
+    fi
+
     if [ -n "$additional_configure_args" ]; then
       # Split additional_configure_args respecting any internal quotation.
       # Otherwise things like --with-cc-opt='-foo -bar' won't work.
       eval additional_configure_args=("$additional_configure_args")
       configure=("${configure[@]}" "${additional_configure_args[@]}")
     fi
-    fi
+
     echo "About to configure nginx with:"
     echo "   $(quote_arguments "${configure[@]}")"
     continue_or_exit "Does this look right?"