fix the march situation and bug introduced in shared libgerbil buildi…

…ng (#792)

* fix the --enable-march situation

there is a gambit configure bug related to this and on the same time
not specifying it is discourage; so we do native by default.

* fix unbound variable

* add --enable-shared build on CI matrix

.github/workflows/ci.yml

@@ -7,12 +7,13 @@ jobs:
       fail-fast: false  # if one fails, do not cancel the other
       matrix:
         gambit-version: ['v4.9.5', 'master']
+        shared-mode: ['', '--enable-shared']
     steps:
       - uses: actions/checkout@v2
       - name: Install dependencies
         run: sudo apt-get -y install openssl libssl-dev sqlite3 libsqlite3-dev
       - name: Configure Gerbil
-        run: ./configure --prefix=/opt/gerbil --with-gambit=${{ matrix.gambit-version }}
+        run: ./configure --prefix=/opt/gerbil --with-gambit=${{ matrix.gambit-version }} ${{ matrix.shared-mode }}
       - name: Create Gerbil version file
         run: echo "(define (gerbil-version-string) \"git-$(git rev-parse --short=8 HEAD)\")" > src/gerbil/runtime/gx-version.scm
       - name: Prepare Build

configure

@@ -22,6 +22,8 @@ Options understood and processed by Gerbil:
   --prefix=PREFIX       where to install Gerbil; default prefix is /opt/gerbil
   --with-gambit=TAG     integrated gambit git tag to check out for the build;
                         defaults to ${default_gambit_tag}
+  --enable-march=ARCH   specify the machine architecture; it can be empty.
+                        defaults to native
 
 Gerbil Standard Library features:
   --enable-libxml       Enable or disable libxml based libraries; disabled by default
@@ -63,6 +65,7 @@ prefix="/opt/gerbil"
 readonly cflags_opt="-foptimize-sibling-calls"
 readonly ldflags_rpath="-Wl,-rpath"
 
+gambit_march="native"
 gambit_tag="${default_gambit_tag}"
 gambit_config="${default_gambit_config}"
 
@@ -83,6 +86,11 @@ while [ $# -gt 0 ]; do
             shift
             ;;
 
+        --enable-march=*)
+            gambit_march=$(echo "$1" | cut -d = -f 2-)
+            shift
+            ;;
+
         --enable-libxml)
             std_enable_feature libxml
             shift
@@ -198,7 +206,7 @@ git submodule update --force || die
 
 (cd src/gambit && git pull origin master && git checkout "${gambit_tag}" && touch configure config.status) || die
 
-gambit_config="--prefix=${gerbil_prefix} ${gambit_config} LDFLAGS=${LDFLAGS} CFLAGS=${CFLAGS}"
+gambit_config="--prefix=${gerbil_prefix} --enable-march=${gambit_march} ${gambit_config} LDFLAGS=${LDFLAGS} CFLAGS=${CFLAGS}"
 (cd src/gambit && ./configure $gambit_config) || die
 
 rm -f build-env.sh

src/build/build-libgerbil.ss

@@ -390,7 +390,7 @@
     (let (libgerbil-ldd (filter (? (not string-empty?)) (string-split ld-options #\space)))
       (if (eq? mode 'shared)
         (invoke-gcc ["-shared" "-o" libgerbil
-                     shared-ld-opts ...
+                     libgerbil-ldd ...
                      gx-gambc-o-paths ...
                      static-module-o-paths ...
                      builtin-modules-o-path