host: Rename host.gni to target_config.gni

Renames host.gni to target_config.gni so all targets have a
target_config.gni, and it's clear which .gni file to use for target
configuration.

Change-Id: I1bd0442a9dc00201bff46eb776a4a59c1d339a4e
diff --git a/BUILDCONFIG.gn b/BUILDCONFIG.gn
index fd625f5..0bcc9a4 100644
--- a/BUILDCONFIG.gn
+++ b/BUILDCONFIG.gn
@@ -31,7 +31,7 @@
   #
   # When this is changed, you must run `ninja -t clean` to remove any files from
   # the previous target's build before building again.
-  pw_target_config = "$dir_pigweed/targets/host/host.gni"
+  pw_target_config = "$dir_pigweed/targets/host/target_config.gni"
 }
 
 # Import variables that provide paths to modules. Pigweed's GN build requires
diff --git a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
index 9436563..f11db7e 100755
--- a/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
+++ b/pw_presubmit/py/pw_presubmit/pigweed_presubmit.py
@@ -120,8 +120,9 @@
          **kwargs)
 
 
-_CLANG_GEN_ARGS = gn_args(pw_target_config='"//targets/host/host.gni"',
-                          pw_target_toolchain='"//pw_toolchain:host_clang_os"')
+_CLANG_GEN_ARGS = gn_args(
+    pw_target_config='"//targets/host/target_config.gni"',
+    pw_target_toolchain='"//pw_toolchain:host_clang_os"')
 
 _DOCS_GEN_ARGS = gn_args(pw_target_config='"//targets/docs/target_config.gni"')
 
@@ -133,7 +134,7 @@
 
 @filter_paths(endswith=format_code.C_FORMAT.extensions)
 def gn_gcc_build(ctx: PresubmitContext):
-    gn_gen(gn_args(pw_target_config='"//targets/host/host.gni"',
+    gn_gen(gn_args(pw_target_config='"//targets/host/target_config.gni"',
                    pw_target_toolchain='"//pw_toolchain:host_gcc_os"'),
            ctx=ctx)
     ninja(ctx=ctx)
@@ -166,7 +167,7 @@
 
 
 def gn_host_tools(ctx: PresubmitContext):
-    gn_gen(gn_args(pw_target_config='"//targets/host/host.gni"',
+    gn_gen(gn_args(pw_target_config='"//targets/host/target_config.gni"',
                    pw_target_toolchain='"//pw_toolchain:host_clang_os"',
                    pw_build_host_tools='true'),
            ctx=ctx)
diff --git a/targets/host/host.gni b/targets/host/target_config.gni
similarity index 100%
rename from targets/host/host.gni
rename to targets/host/target_config.gni