diff --git a/configure.ac b/configure.ac
index 687c5c974..31e57a3cd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -283,7 +283,7 @@ AC_ARG_ADAPTERS([
   HIDAPI_ADAPTERS,
   HIDAPI_USB1_ADAPTERS,
   LIBFTDI_ADAPTERS,
-  LIBFTDI_USB1_ADAPTERS
+  LIBFTDI_USB1_ADAPTERS,
   LIBGPIOD_ADAPTERS,
   SERIAL_PORT_ADAPTERS,
   PCIE_ADAPTERS,
@@ -372,10 +372,6 @@ AS_CASE([$host_os],
       AC_MSG_ERROR([sysfsgpio is only available on linux])
     ])
 
-    AS_IF([test "x$enable_linuxgpiod" = "xyes"], [
-      AC_MSG_ERROR([linuxgpiod is only available on linux])
-    ])
-
     AS_CASE([$host_os], [freebsd*], [],
     [
       AS_IF([test "x$build_rshim" = "xyes"], [
@@ -722,7 +718,7 @@ PROCESS_ADAPTERS([HIDAPI_ADAPTERS], ["x$use_hidapi" = "xyes"], [hidapi])
 PROCESS_ADAPTERS([HIDAPI_USB1_ADAPTERS], ["x$use_hidapi" = "xyes" -a "x$use_libusb1" = "xyes"], [hidapi and libusb-1.x])
 PROCESS_ADAPTERS([LIBFTDI_ADAPTERS], ["x$use_libftdi" = "xyes"], [libftdi])
 PROCESS_ADAPTERS([LIBFTDI_USB1_ADAPTERS], ["x$use_libftdi" = "xyes" -a "x$use_libusb1" = "xyes"], [libftdi and libusb-1.x])
-PROCESS_ADAPTERS([LIBGPIOD_ADAPTERS], ["x$use_libgpiod" = "xyes"], [libgpiod])
+PROCESS_ADAPTERS([LIBGPIOD_ADAPTERS], ["x$use_libgpiod" = "xyes"], [Linux libgpiod])
 PROCESS_ADAPTERS([LIBJAYLINK_ADAPTERS], ["x$use_internal_libjaylink" = "xyes" -o "x$use_libjaylink" = "xyes"], [libjaylink-0.2])
 PROCESS_ADAPTERS([PCIE_ADAPTERS], ["x$is_linux" = "xyes"], [Linux build])
 PROCESS_ADAPTERS([SERIAL_PORT_ADAPTERS], ["x$can_build_buspirate" = "xyes"],
@@ -889,6 +885,11 @@ m4_foreach([adapter], [USB1_ADAPTERS,
 		],
 		[no], [
 			echo "$s"no
+		],
+		[
+			AC_MSG_ERROR(m4_normalize([
+				Error in [adapter] "ADAPTER_ARG([adapter])": Variable "ADAPTER_VAR([adapter])"
+				has invalid value "$ADAPTER_VAR([adapter])".]))
 	])
 ])
 echo