lgtm: Build external dependencies for a more complete analysis

The build system is a bit limited, only the repository directory and
LGTM_WORKSPACE is writable.  sudo doesn't work at all, for others we
don't have enough permission.

.lgtm.yml

@@ -6,6 +6,28 @@ queries:
 
 extraction:
   cpp:
+    prepare:
+      packages:
+        # for tss2
+        - libssl-dev
+    after_prepare:
+      - export DEPS_BUILD_DIR=$LGTM_WORKSPACE/deps
+      - mkdir -p $DEPS_BUILD_DIR
+      - export DEPS_PREFIX=$DEPS_BUILD_DIR/usr
+      - mkdir -p $DEPS_PREFIX
+      - export PKG_CONFIG_PATH="$DEPS_PREFIX/lib/pkgconfig:$PKG_CONFIG_PATH"
+      - export LD_LIBRARY_PATH="$DEPS_PREFIX/lib:$LD_LIBRARY_PATH"
+      - mkdir -p $LGTM_WORKSPACE/bin
+      # sudo doesn't work on the build hosts
+      - ln -s /usr/bin/nice $LGTM_WORKSPACE/bin/sudo
+      # for ldconfig we don't have enough permissions
+      - ln -s /bin/true $LGTM_WORKSPACE/bin/ldconfig
+      # likewise for apt-get
+      - ln -s /bin/echo $LGTM_WORKSPACE/bin/apt-get
+      - export PATH=$LGTM_WORKSPACE/bin:$PATH
+      - export TEST=all
+      - ./scripts/test.sh deps
+      - rm $LGTM_WORKSPACE/bin/*
     configure:
       command:
         # follows the "all" build in test.sh (without custom-compiled stuff)
@@ -19,4 +41,4 @@ extraction:
             --disable-kernel-wfp --disable-kernel-iph --disable-winhttp
             --disable-af-alg --disable-coverage
             --disable-python-eggs-install
-            --disable-botan --disable-wolfssl --disable-tss-tss2
+            --disable-monolithic --disable-leak-detective