ENH: improve build naming without git

- now defaults to the project-version when absolutely nothing else is
  known

STYLE: simplify internal calling in wmakeBuildInfo

wmake/wmakeBuildInfo

@@ -30,6 +30,7 @@
 #
 # Environment
 #     - WM_PROJECT_DIR
+#     - WM_PROJECT_VERSION
 #     - WM_DIR              (unset defaults to WM_PROJECT_DIR/wmake)
 #
 # Note
@@ -179,6 +180,13 @@ declare -A metaInfo
 #
 getMakeInfo()
 {
+    if [ "${#makeInfo[*]}" -eq 4 ]
+    then
+        ##echo "use cached value for make info" 1>&2
+        return 0
+    fi
+    ##echo "get make info" 1>&2
+
     local api patch build branch
     makeInfo=()
 
@@ -206,7 +214,6 @@ getMakeInfo()
     makeInfo[patch]="${patch:-0}"  # default is 0
     makeInfo[branch]="$branch"
     makeInfo[build]="$build"
-    makeInfo[cached]=true
 }
 
 
@@ -224,6 +231,13 @@ getMakeInfo()
 #
 getMetaInfo()
 {
+    if [ "${#metaInfo[*]}" -eq 4 ]
+    then
+        ##echo "use cached value for meta info" 1>&2
+        return 0
+    fi
+    ##echo "get meta info" 1>&2
+
     local api patch build branch
     metaInfo=()
 
@@ -242,7 +256,6 @@ getMetaInfo()
     metaInfo[patch]="${patch:-0}"  # default is 0
     metaInfo[branch]="$branch"
     metaInfo[build]="$build"
-    metaInfo[cached]=true
 }
 
 
@@ -257,14 +270,14 @@ getMetaInfo()
 #
 getApi()
 {
-    [ -n "${makeInfo[cached]}" ] || getMakeInfo
+    getMakeInfo
 
     # Local copy
     local api="${makeInfo[api]}"
 
     if [ -z "$api" ]
     then
-        [ -n "${metaInfo[cached]}" ] || getMetaInfo
+        getMetaInfo
         api="${metaInfo[api]}"
     fi
 
@@ -284,7 +297,7 @@ getApi()
 #
 getPatchLevel()
 {
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
+    getMetaInfo
 
     # Local copy
     local value="${metaInfo[patch]}"
@@ -301,10 +314,8 @@ getPatchLevel()
 # Report make info
 reportMakeInfo()
 {
-    local key
+    getMakeInfo
-
+    getMetaInfo
-    [ -n "${makeInfo[cached]}" ] || getMakeInfo
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
 
     local patch="${metaInfo[patch]}" # <- From meta-info only
     makeInfo[patch]="${patch:=0}"    # Extra safety
@@ -320,9 +331,7 @@ reportMakeInfo()
 # Report meta info
 reportMetaInfo()
 {
-    local key
+    getMetaInfo
-
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
 
     local patch="${metaInfo[patch]}" # <- From meta-info only
     metaInfo[patch]="${patch:=0}"    # Extra safety
@@ -343,15 +352,27 @@ checkDiff()
     local verbose="$1"
     local key diff
 
-    [ -n "${makeInfo[cached]}" ] || getMakeInfo
+    getMakeInfo
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
+    getMetaInfo
 
     for key in api patch branch build
     do
         if [ "${makeInfo[$key]}" != "${metaInfo[$key]}" ]
+        then
+            case "$key" in
+            (branch | build)
+                # Only trigger when make info (branch, build) are non-empty
+                if [ -n "${makeInfo[$key]}" ]
                 then
                     diff="$diff $key"
                 fi
+
+                ;;
+            (*)
+                diff="$diff $key"
+                ;;
+            esac
+        fi
     done
 
     if [ "$verbose" = verbose ] && [ -n "$diff" ]
@@ -365,7 +386,8 @@ checkDiff()
         done
     fi
 
-    test -z "$diff"
+    # No diffs, but never permit entirely empty values for build.
+    test -z "$diff" || test -z "${makeInfo[build]}${metaInfo[build]}"
 }
 
 
@@ -374,8 +396,8 @@ checkDiff()
 #
 performUpdate()
 {
-    [ -n "${makeInfo[cached]}" ] || getMakeInfo
+    getMakeInfo
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
+    getMetaInfo
 
     # Local copies of the make info
     local api="${makeInfo[api]}"
@@ -389,6 +411,9 @@ performUpdate()
     [ -n "$branch" ] || branch="${metaInfo[branch]}"
     [ -n "$build" ] || build="${metaInfo[build]}"
 
+    # Fallback to WM_PROJECT_VERSION alone
+    [ -n "$build" ] || build="${WM_PROJECT_VERSION:-unknown}"
+
     local outputFile
 
     # build-info
@@ -447,8 +472,8 @@ performFiltering()
         exit 2
     }
 
-    [ -n "${makeInfo[cached]}" ] || getMakeInfo
+    getMakeInfo
-    [ -n "${metaInfo[cached]}" ] || getMetaInfo
+    getMetaInfo
 
     # Local copies of the make info
     local api="${makeInfo[api]}"
@@ -479,7 +504,8 @@ performFiltering()
     if [ -z "$build" ]
     then
         build="${metaInfo[build]}"
-        build="nogit${build:+-$build}"
+        # Fallback to WM_PROJECT_VERSION
+        build="${build:-${WM_PROJECT_VERSION:-unknown}}"
     fi
 
     sed \