diff --git a/config.guess b/config.guess
index c7f4c3294..039dc38e3 100644
--- a/config.guess
+++ b/config.guess
@@ -942,6 +942,9 @@ EOF
     *:SerenityOS:*:*)
         GUESS=$UNAME_MACHINE-pc-serenity
         ;;
+    *:HarmonyOS:*:*)
+        GUESS=$UNAME_MACHINE-unknown-linux-ohos
+        ;;
     *:Interix*:*)
 	case $UNAME_MACHINE in
 	    x86)
@@ -954,7 +957,7 @@ EOF
 		GUESS=ia64-unknown-interix$UNAME_RELEASE
 		;;
 	esac ;;
-    i*:UWIN*:*)
+    i*:UWIN:*:*)
 	GUESS=$UNAME_MACHINE-pc-uwin
 	;;
     amd64:CYGWIN*:*:* | x86_64:CYGWIN*:*:*)
diff --git a/config.h.in b/config.h.in
index 67db18f75..ab67d3973 100644
--- a/config.h.in
+++ b/config.h.in
@@ -35,8 +35,13 @@
 # undef HAVE_LIBZ
 # undef HAVE_LIBBZ2
 # undef HAVE_LROUND
+# undef HAVE_LLROUND
+# undef HAVE_NAN
+# undef HAVE_FMIN
+# undef HAVE_FMAX
 # undef HAVE_SYS_WAIT_H
 # undef WORDS_BIGENDIAN
+# undef UINT64_T_AND_ULONG_SAME
 
 #ifdef HAVE_INTTYPES_H
 # include  <inttypes.h>
diff --git a/configure.ac b/configure.ac
index 9ad90e571..6dac7ccc1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -274,7 +274,9 @@ AC_MSG_RESULT($do_times)
 AC_CHECK_HEADERS(dlfcn.h dl.h, break)
 
 DLLIB=''
-AC_CHECK_LIB(dl,dlopen,[DLLIB=-ldl])
+# First check if dlopen is in libc (musl, OHOS, etc.)
+AC_CHECK_FUNC(dlopen, [DLLIB=],
+  [AC_CHECK_LIB(dl,dlopen,[DLLIB=-ldl])])
 if test -z "$DLLIB" ; then
 AC_CHECK_LIB(dld,shl_load,[DLLIB=-ldld])
 fi
@@ -363,11 +365,26 @@ AC_CHECK_FUNCS(realpath)
 # Check that these functions exist. They are mostly C99
 # functions that older compilers may not yet support.
 AC_CHECK_FUNCS(fopen64)
+# On musl-based systems, fopen64 may need _LARGEFILE64_SOURCE to be
+# declared. Try again with it defined if the first check failed.
+if test "$ac_cv_func_fopen64" != yes; then
+  iverilog_saved_cppflags="$CPPFLAGS"
+  CPPFLAGS="-D_LARGEFILE64_SOURCE $CPPFLAGS"
+  AC_CHECK_FUNCS(fopen64,
+    [AC_DEFINE([_LARGEFILE64_SOURCE], [1],
+      [Define to 1 if _LARGEFILE64_SOURCE is needed for fopen64])])
+  CPPFLAGS="$iverilog_saved_cppflags"
+fi
 # The following math functions may be defined in the math library so look
 # in the default libraries first and then look in -lm for them. On some
 # systems we may need to use the compiler in C99 mode to get a definition.
 # autoconf >= 2.70 will enable C99 if it is available. For older autoconf
 # versions, we requested C99 mode earlier with AC_PROG_CC_C99.
+AH_TEMPLATE([HAVE_LROUND], [Define if lround is available])
+AH_TEMPLATE([HAVE_LLROUND], [Define if llround is available])
+AH_TEMPLATE([HAVE_NAN], [Define if nan is available])
+AH_TEMPLATE([HAVE_FMIN], [Define if fmin is available])
+AH_TEMPLATE([HAVE_FMAX], [Define if fmax is available])
 AC_SEARCH_LIBS([lround], [m], [AC_DEFINE([HAVE_LROUND], [1])])
 AC_SEARCH_LIBS([llround], [m], [AC_DEFINE([HAVE_LLROUND], [1])])
 AC_SEARCH_LIBS([nan], [m], [AC_DEFINE([HAVE_NAN], [1])])
@@ -397,7 +414,8 @@ uint64_t uival = 1;
 result &= check(uival);
 return !result;]])],
    [AC_MSG_RESULT(no)],
-   [AC_DEFINE([UINT64_T_AND_ULONG_SAME], [1]) AC_MSG_RESULT(yes)])
+   [AH_TEMPLATE([UINT64_T_AND_ULONG_SAME], [Define if uint64_t and unsigned long are the same type])
+    AC_DEFINE([UINT64_T_AND_ULONG_SAME], [1]) AC_MSG_RESULT(yes)])
 
 # Linker option used when compiling the target
 AX_LD_RDYNAMIC