fix(cmake): properly check that git describe returns a real tag (semversioned).

Signed-off-by: Federico Di Pierro <nierro92@gmail.com>

cmake/modules/GetFalcoVersion.cmake

@@ -19,6 +19,10 @@ if(NOT FALCO_VERSION)
   # Try to obtain the exact git tag
   git_get_exact_tag(FALCO_TAG)
   if(NOT FALCO_TAG)
+      # Obtain the closest tag
+      git_describe(FALCO_VERSION "--always" "--tags" "--abbrev=7")
+      string(REGEX MATCH "^[0-9]+.[0-9]+.[0-9]+$" FALCO_TAG ${FALCO_VERSION})
+      if(FALCO_VERSION MATCHES "NOTFOUND$" OR FALCO_TAG STREQUAL "")
         # Fetch current hash
         get_git_head_revision(refspec FALCO_HASH)
         if(NOT FALCO_HASH OR FALCO_HASH MATCHES "NOTFOUND$")
@@ -42,6 +46,9 @@ if(NOT FALCO_VERSION)
             endif()
           endif()
         endif()
+      endif()
+      # Format FALCO_VERSION to be semver with prerelease and build part
+      string(REPLACE "-g" "+" FALCO_VERSION "${FALCO_VERSION}")
   else()
     # A tag has been found: use it as the Falco version
     set(FALCO_VERSION "${FALCO_TAG}")