diff --git a/configure.ac b/configure.ac
index 291e854a4..687c5c974 100644
--- a/configure.ac
+++ b/configure.ac
@@ -414,6 +414,8 @@ AS_CASE(["${host_cpu}"],
     parport_use_ppdev=yes
 ])
 
+can_build_buspirate=yes
+
 AS_CASE([$host],
   [*-cygwin*], [
     is_win32=yes
@@ -445,12 +447,12 @@ AS_CASE([$host],
     ])
     parport_use_giveio=yes
 
-    AS_IF([test "x$enable_buspirate" = "xyes"], [
-      AC_MSG_ERROR([buspirate currently not supported by MinGW32 hosts])
+    AS_IF([test "x$ADAPTER_VAR([buspirate])" = "xyes"], [
+      AC_MSG_ERROR([The Bus Pirate adapter is currently not supported by MinGW32 hosts.])
     ])
 
     # In case enable_buspirate=auto, make sure it will not be built.
-    enable_buspirate=no
+    can_build_buspirate=no
 
     AC_SUBST([HOST_CPPFLAGS], ["-D__USE_MINGW_ANSI_STDIO -DFD_SETSIZE=128"])
   ],
@@ -594,12 +596,6 @@ AS_IF([test "x$build_gw16012" = "xyes"], [
   AC_DEFINE([BUILD_GW16012], [0], [0 if you don't want the Gateworks GW16012 driver.])
 ])
 
-AS_IF([test "x$enable_buspirate" != "xno"], [
-  AC_DEFINE([BUILD_BUSPIRATE], [1], [1 if you want the Buspirate JTAG driver.])
-], [
-  AC_DEFINE([BUILD_BUSPIRATE], [0], [0 if you don't want the Buspirate JTAG driver.])
-])
-
 AS_IF([test "x$use_internal_jimtcl" = "xyes"], [
   AS_IF([test -f "$srcdir/jimtcl/configure"], [
     AS_IF([test "x$use_internal_jimtcl_maintainer" = "xyes"], [
@@ -712,7 +708,7 @@ m4_define([PROCESS_ADAPTERS], [
 		])
 	], [
 		AS_IF([test "x$ADAPTER_VAR([adapter])" = "xyes"], [
-			AC_MSG_ERROR([$3 is required for [adapter] ADAPTER_DESC([adapter]).])
+			AC_MSG_ERROR([$3 is required for [adapter] "ADAPTER_DESC([adapter])".])
 		])
 		ADAPTER_VAR([adapter])=no
 		AC_DEFINE([BUILD_]ADAPTER_SYM([adapter]), [0], [0 if you do not want the ]ADAPTER_DESC([adapter]).)
@@ -729,6 +725,8 @@ PROCESS_ADAPTERS([LIBFTDI_USB1_ADAPTERS], ["x$use_libftdi" = "xyes" -a "x$use_li
 PROCESS_ADAPTERS([LIBGPIOD_ADAPTERS], ["x$use_libgpiod" = "xyes"], [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"],
+                                         [internal error: validation should happen beforehand])
 PROCESS_ADAPTERS([DUMMY_ADAPTER], [true], [unused])
 
 AS_IF([test "x$enable_linuxgpiod" != "xno"], [
@@ -783,7 +781,6 @@ AM_CONDITIONAL([USB_BLASTER_DRIVER], [test "x$enable_usb_blaster" != "xno" -o "x
 AM_CONDITIONAL([AMTJTAGACCEL], [test "x$build_amtjtagaccel" = "xyes"])
 AM_CONDITIONAL([GW16012], [test "x$build_gw16012" = "xyes"])
 AM_CONDITIONAL([REMOTE_BITBANG], [test "x$build_remote_bitbang" = "xyes"])
-AM_CONDITIONAL([BUSPIRATE], [test "x$enable_buspirate" != "xno"])
 AM_CONDITIONAL([SYSFSGPIO], [test "x$build_sysfsgpio" = "xyes"])
 AM_CONDITIONAL([USE_LIBUSB1], [test "x$use_libusb1" = "xyes"])
 AM_CONDITIONAL([IS_CYGWIN], [test "x$is_cygwin" = "xyes"])
diff --git a/src/jtag/drivers/Makefile.am b/src/jtag/drivers/Makefile.am
index e404afe9f..8be834859 100644
--- a/src/jtag/drivers/Makefile.am
+++ b/src/jtag/drivers/Makefile.am
@@ -143,7 +143,7 @@ endif
 if ARMJTAGEW
 DRIVERFILES += %D%/arm-jtag-ew.c
 endif
-if BUSPIRATE
+if BUS_PIRATE
 DRIVERFILES += %D%/buspirate.c
 endif
 if REMOTE_BITBANG
diff --git a/src/jtag/interfaces.c b/src/jtag/interfaces.c
index c24ead8cd..67f0838e3 100644
--- a/src/jtag/interfaces.c
+++ b/src/jtag/interfaces.c
@@ -102,7 +102,7 @@ struct adapter_driver *adapter_drivers[] = {
 #if BUILD_ARMJTAGEW == 1
 		&armjtagew_adapter_driver,
 #endif
-#if BUILD_BUSPIRATE == 1
+#if BUILD_BUS_PIRATE == 1
 		&buspirate_adapter_driver,
 #endif
 #if BUILD_REMOTE_BITBANG == 1