diff -Naurp lrzip-next-0.12.6.orig/configure.ac lrzip-next-0.12.6/configure.ac
--- lrzip-next-0.12.6.orig/configure.ac	2024-01-27 08:42:15.000000000 -0500
+++ lrzip-next-0.12.6/configure.ac	2024-03-11 16:27:53.972571412 -0400
@@ -168,16 +168,19 @@ AC_CHECK_LIB(gcrypt, gcry_md_open, ,
 AC_CHECK_FUNCS(mmap strerror)
 AC_CHECK_FUNCS(getopt_long)
 
-AX_PTHREAD
-LIBS="$PTHREAD_LIBS $LIBS"
-AS_IF([test x"$debug" = xyes],
-	 CFLAGS="-g -Og -DDEBUG"
-	 CXXFLAGS="-g -Og -DDEBUG",
-	 CFLAGS="$CFLAGS"
-	 CXXFLAGS="$CXXFLAGS")
-
-CFLAGS+=" $PTHREAD_CFLAGS"
-CXXFLAGS+=" $PTHREAD_CFLAGS"
+ACX_PTHREAD([
+	LIBS="$LIBS $PTHREAD_LIBS"
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS"
+	CC="$PTHREAD_CC"
+	CXX="$PTHREAD_CXX"
+	AC_SUBST([LIBS])
+	AC_SUBST([CFLAGS])
+	AC_SUBST([CXXFLAGS])
+	AC_SUBST([CC])
+	AC_SUBST([CXX])
+	],
+	[AC_MSG_ERROR([POSIX threads support is required])])
 
 ## test for ARM or other non x86 processor
 ## must use -DNOJIT for compiling zpaq