fish: cbl_bld_llvm_fast: Make a little bit more flexible

Signed-off-by: Nathan Chancellor <[email protected]>

fish/functions/cbl_bld_llvm_fast.fish

@@ -3,20 +3,36 @@
 # Copyright (C) 2024 Nathan Chancellor
 
 function cbl_bld_llvm_fast -d "Quickly build a version of LLVM from current tree"
-    in_tree llvm
-    or return 128
+    set bld_llvm_args $argv
+    if contains -- -l $bld_llvm_args
+        set llvm_flag -l
+    end
+    if contains -- --llvm-folder $bld_llvm_args
+        set llvm_flag --llvm-folder
+    end
+    if set -q llvm_flag
+        set llvm_folder $bld_llvm_args[(math (contains -i -- $llvm_flag $bld_llvm_args) + 1)]
+        set bld_folder (tbf $llvm_folder)
+    end
+    if not set -q llvm_folder
+        in_tree llvm
+        or return 128
+
+        set llvm_folder .
+        set bld_folder (tbf)
+    end
 
     cbl_clone_repo tc-build
     or return
 
     $CBL_GIT/tc-build/build-llvm.py \
         --assertions \
-        --build-folder (tbf) \
+        --build-folder $bld_folder \
         --build-stage1-only \
         --build-targets distribution \
-        --llvm-folder . \
+        --llvm-folder $llvm_folder \
         --projects clang lld \
         --quiet-cmake \
         --show-build-commands \
-        $argv
+        $bld_llvm_args
 end