pw_build: Allow non-present deps in remove_public_deps

Change-Id: Ie349a944d2ed0b04f51030cca0411d7fd8ab35c5
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/21821
Reviewed-by: Alexei Frolov <frolv@google.com>
Commit-Queue: Wyatt Hepler <hepler@google.com>
diff --git a/pw_build/target_types.gni b/pw_build/target_types.gni
index 1564e73..7590f2d 100644
--- a/pw_build/target_types.gni
+++ b/pw_build/target_types.gni
@@ -71,9 +71,10 @@
       public_deps = []
     }
     if (defined(remove_public_deps)) {
-      if (remove_public_deps[0] == "*") {
+      if (remove_public_deps != [] && remove_public_deps[0] == "*") {
         public_deps = []
       } else {
+        public_deps += remove_public_deps
         public_deps -= remove_public_deps
       }
     }
@@ -117,9 +118,10 @@
       public_deps = []
     }
     if (defined(remove_public_deps)) {
-      if (remove_public_deps[0] == "*") {
+      if (remove_public_deps != [] && remove_public_deps[0] == "*") {
         public_deps = []
       } else {
+        public_deps += remove_public_deps
         public_deps -= remove_public_deps
       }
     }
@@ -165,9 +167,10 @@
       public_deps = []
     }
     if (defined(remove_public_deps)) {
-      if (remove_public_deps[0] == "*") {
+      if (remove_public_deps != [] && remove_public_deps[0] == "*") {
         public_deps = []
       } else {
+        public_deps += remove_public_deps
         public_deps -= remove_public_deps
       }
     }
@@ -216,9 +219,10 @@
       public_deps = []
     }
     if (defined(remove_public_deps)) {
-      if (remove_public_deps[0] == "*") {
+      if (remove_public_deps != [] && remove_public_deps[0] == "*") {
         public_deps = []
       } else {
+        public_deps += remove_public_deps
         public_deps -= remove_public_deps
       }
     }