build: Install bridge in libexec

Users aren't intended to run the server directly so it shouldn't be
included in their PATH.

Change-Id: Idc49664a7a07142ee27aac1318066bba6f67a6fd
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/src/meson.build b/src/meson.build
index 00394f0..7d57e5a 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -8,7 +8,7 @@
   required: false)
 assert(has_cli11, 'CLI11 is required')
 
-executable(
+kcsbridged = executable(
   'kcsbridged',
   'kcsbridged.cpp',
   implicit_include_directories: false,
@@ -32,4 +32,4 @@
     '-DBOOST_COROUTINES_NO_DEPRECATION_WARNING',
   ],
   install: true,
-  install_dir: get_option('bindir'))
+  install_dir: get_option('libexecdir'))