Avoid AX_COMPARE_VERSION dependency

configure.ac

@@ -610,26 +610,29 @@ AC_ARG_WITH([r8169-kernel],
     ]
 )
 
-AX_COMPARE_VERSION(["$kernel_r8169"], [ge], [5.0.0],
-    AC_SUBST(R8169_KERNEL_5, [1]),
-    AC_SUBST(R8169_KERNEL_5, [0])
-)
-
 if test "x${enable_r8169}" = "x1"; then
     AC_MSG_CHECKING([for kernel for r8169 driver])
 
     kernels=`ls -1 ${srcdir}/devices/ | grep -oE "^r8169-.*-" | cut -d "-" -f 2 | uniq`
-    kernels5=`ls -1 ${srcdir}/devices/r8169/ | grep -oE "^r8169_main-.*-" | cut -d "-" -f 2 | uniq`
+    kernels_subdir=`ls -1 ${srcdir}/devices/r8169/ | grep -oE "^r8169_main-.*-" | cut -d "-" -f 2 | uniq`
     found=0
-    for k in $kernels $kernels5; do
+    found_subdir=0
+    for k in $kernels; do
         if test "$kernel_r8169" = "$k"; then
             found=1
         fi
     done
+    for k in $kernels_subdir; do
+        if test "$kernel_r8169" = "$k"; then
+            found=1
+            found_subdir=1
+        fi
+    done
     if test $found -ne 1; then
         AC_MSG_ERROR([kernel $kernel_r8169 not available for r8169 driver!])
     fi
 
+    AC_SUBST(R8169_IN_SUBDIR, [$found_subdir])
     AC_MSG_RESULT([$kernel_r8169])
 fi
 

devices/Kbuild.in

@@ -83,7 +83,7 @@ ifeq (@ENABLE_IGC@,1)
 endif
 
 ifeq (@ENABLE_R8169@,1)
-ifeq (@R8169_KERNEL_5@,1)
+ifeq (@R8169_IN_SUBDIR@,1)
 	obj-m += r8169/
 else
 	EC_R8169_OBJ := r8169-@KERNEL_R8169@-ethercat.o

devices/r8169/Kbuild.in

@@ -41,7 +41,7 @@ REV := $(shell if test -s $(TOPDIR)/revision; then \
 	fi)
 
 ifeq (@ENABLE_R8169@,1)
-ifeq (@R8169_KERNEL_5@,1)
+ifeq (@R8169_IN_SUBDIR@,1)
 	obj-m += ec_r8169.o
 
 	ec_r8169-objs := \