Revert "config: cache results of kernel checks (openzfs#17106)"

This reverts commit dd2a46b.

Author: jcadduono

config/kernel.m4

@@ -465,11 +465,6 @@ AC_DEFUN([ZFS_AC_KERNEL], [
 	AC_SUBST(LINUX)
 	AC_SUBST(LINUX_OBJ)
 	AC_SUBST(LINUX_VERSION)
-
-	dnl # create a relatively unique numeric checksum based on the kernel
-	dnl # version and path. this is included in the cache key below,
-	dnl # allowing different cached values for different kernels
-	_zfs_linux_cache_checksum=$(echo ${kernelsrc} {$kernelbuild} ${kernsrcver} | cksum | cut -f1 -d' ')
 ])
 
 AC_DEFUN([ZFS_AC_KERNEL_VERSION_WARNING], [
@@ -817,18 +812,14 @@ dnl # must never depend on the results of previous tests.  Each test
 dnl # needs to be entirely independent.
 dnl #
 AC_DEFUN([ZFS_LINUX_TEST_SRC], [
-	cachevar="zfs_cv_kernel_[$1]_$_zfs_linux_cache_checksum"
-	eval "cacheval=\$$cachevar"
-	AS_IF([test "x$cacheval" = "x"], [
-		ZFS_LINUX_CONFTEST_C([ZFS_LINUX_TEST_PROGRAM([[$2]], [[$3]],
-		    [["Dual BSD/GPL"]])], [$1])
-		ZFS_LINUX_CONFTEST_MAKEFILE([$1], [yes], [$4])
-
-		AS_IF([ test -n "$5" ], [
-			ZFS_LINUX_CONFTEST_C([ZFS_LINUX_TEST_PROGRAM(
-			    [[$2]], [[$3]], [[$5]])], [$1_license])
-			ZFS_LINUX_CONFTEST_MAKEFILE([$1_license], [yes], [$4])
-		])
+	ZFS_LINUX_CONFTEST_C([ZFS_LINUX_TEST_PROGRAM([[$2]], [[$3]],
+	    [["Dual BSD/GPL"]])], [$1])
+	ZFS_LINUX_CONFTEST_MAKEFILE([$1], [yes], [$4])
+
+	AS_IF([ test -n "$5" ], [
+		ZFS_LINUX_CONFTEST_C([ZFS_LINUX_TEST_PROGRAM(
+		    [[$2]], [[$3]], [[$5]])], [$1_license])
+		ZFS_LINUX_CONFTEST_MAKEFILE([$1_license], [yes], [$4])
 	])
 ])
 
@@ -840,23 +831,14 @@ dnl # $2 - run on success (valid .ko generated)
 dnl # $3 - run on failure (unable to compile)
 dnl #
 AC_DEFUN([ZFS_LINUX_TEST_RESULT], [
-	cachevar="zfs_cv_kernel_[$1]_$_zfs_linux_cache_checksum"
-	AC_CACHE_VAL([$cachevar], [
-		AS_IF([test -d build/$1], [
-			AS_IF([test -f build/$1/$1.ko], [
-				eval "$cachevar=yes"
-			], [
-				eval "$cachevar=no"
-			])
-		], [
-			AC_MSG_ERROR([
+	AS_IF([test -d build/$1], [
+		AS_IF([test -f build/$1/$1.ko], [$2], [$3])
+	], [
+		AC_MSG_ERROR([
 	*** No matching source for the "$1" test, check that
 	*** both the test source and result macros refer to the same name.
-			])
 		])
 	])
-	eval "cacheval=\$$cachevar"
-	AS_IF([test "x$cacheval" = "xyes"], [$2], [$3])
 ])
 
 dnl #
@@ -885,24 +867,15 @@ dnl # verify symbol exports, unless --enable-linux-builtin was provided to
 dnl # configure.
 dnl #
 AC_DEFUN([ZFS_LINUX_TEST_RESULT_SYMBOL], [
-	cachevar="zfs_cv_kernel_[$1]_$_zfs_linux_cache_checksum"
-	AC_CACHE_VAL([$cachevar], [
-		AS_IF([ ! test -f build/$1/$1.ko], [
-			eval "$cachevar=no"
+	AS_IF([ ! test -f build/$1/$1.ko], [
+		$5
+	], [
+		AS_IF([test "x$enable_linux_builtin" != "xyes"], [
+			ZFS_CHECK_SYMBOL_EXPORT([$2], [$3], [$4], [$5])
 		], [
-			AS_IF([test "x$enable_linux_builtin" != "xyes"], [
-				ZFS_CHECK_SYMBOL_EXPORT([$2], [$3], [
-					eval "$cachevar=yes"
-				], [
-					eval "$cachevar=no"
-				])
-			], [
-				eval "$cacheval=yes"
-			])
+			$4
 		])
 	])
-	eval "cacheval=\$$cachevar"
-	AS_IF([test "x$cacheval" = "xyes"], [$4], [$5])
 ])
 
 dnl #