diff --git a/configure.ac b/configure.ac
index 069ae75ab..9afcf2b0d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -434,6 +434,7 @@ RB_CHK_SYSHEADER(bitset, [BITSET])
 RB_CHK_SYSHEADER(string_view, [STRING_VIEW])
 RB_CHK_SYSHEADER(optional, [OPTIONAL])
 RB_CHK_SYSHEADER(new, [NEW])
+RB_CHK_SYSHEADER(regex, [REGEX])
 
 dnl unix platform
 RB_CHK_SYSHEADER(unistd.h, [UNISTD_H])
@@ -1191,15 +1192,6 @@ fi
 
 
 
-dnl
-dnl PCRE2 support
-dnl
-
-PKG_CHECK_MODULES(PCRE, [libpcre2-8], [have_pcre="yes"], [have_pcre="no"])
-AM_CONDITIONAL([PCRE], [test "x$have_pcre" = "xyes"])
-
-
-
 dnl
 dnl libmagic support
 dnl