Show b2 binary and source version

ci/common_install.sh

@@ -176,9 +176,10 @@ if [[ "$B2_DONT_BOOTSTRAP" != "1" ]]; then
     trap show_bootstrap_log ERR
     # Check if b2 already exists. This would (only) happen in a caching scenario. The purpose of caching is to save time by not recompiling everything.
     # The user may clear cache or delete b2 beforehand if they wish to rebuild.
-    if [ ! -f b2 ] || ! b2_version_output=$(./b2 --version); then
+    if [ ! -f b2 ]; then
         ${B2_WRAPPER} ./bootstrap.sh
     else
+        b2_version_output=$(./b2 --version)
         # b2 expects versions to match
         engineversion=$(echo "$b2_version_output" | tr -s ' ' | cut -d' ' -f2 | cut -d'-' -f1)
         enginemajorversion=$(echo "${engineversion}" | cut -d'.' -f1)
@@ -188,6 +189,11 @@ if [[ "$B2_DONT_BOOTSTRAP" != "1" ]]; then
         if [[ "${enginemajorversion}" == "${coremajorversion}" ]] && [[ "${engineminorversion}" == "${coreminorversion}" ]]; then
             echo "b2 already exists and has the same version number"
         else
+            if [[ "$engineversion" =~ ^[0-9]\.[0-9]\. ]]; then
+                echo "b2 binary version: $enginemajorversion:$engineminorversion vs source version $coremajorversion:$coreminorversion"
+            else
+                echo "Unable to extract B2 version from $b2_version_output"
+            fi
             ${B2_WRAPPER} ./bootstrap.sh
         fi
     fi