diff --git a/shells/ksh93/Makefile b/shells/ksh93/Makefile
--- a/shells/ksh93/Makefile
+++ b/shells/ksh93/Makefile
@@ -14,7 +14,7 @@
 
 PORTNAME=	ksh93
 DISTVERSION=	93u
-PORTREVISION=	1
+PORTREVISION=	2
 PORTEPOCH=	2
 CATEGORIES=	shells
 DIST_SUBDIR=	ksh93
@@ -25,9 +25,6 @@
 
 LICENSE=	EPL
 
-BROKEN_aarch64=	Fails to compile: needs sbrk
-BROKEN_riscv64=	Fails to compile: needs sbrk
-
 USES=		compiler:c11
 
 USE_GITHUB=	yes
diff --git a/shells/ksh93/files/patch-src_lib_libast_vmalloc_vmbest.c b/shells/ksh93/files/patch-src_lib_libast_vmalloc_vmbest.c
new file mode 100644
--- /dev/null
+++ b/shells/ksh93/files/patch-src_lib_libast_vmalloc_vmbest.c
@@ -0,0 +1,25 @@
+--- src/lib/libast/vmalloc/vmbest.c.orig
++++ src/lib/libast/vmalloc/vmbest.c
+@@ -1169,6 +1169,7 @@
+ }
+ #endif /* _mem_win32 */
+ 
++#undef _mem_sbrk
+ #if _mem_sbrk /* getting space via brk/sbrk - not concurrent-ready */
+ static Void_t* sbrkmem(Void_t* caddr, size_t csize, size_t nsize)
+ {
+@@ -1265,10 +1266,13 @@
+ 		}
+ 	}
+ 	else if(nsize == 0)
+-	{	Vmuchar_t	*addr = (Vmuchar_t*)sbrk(0);
++	{
++#if 0
++		Vmuchar_t	*addr = (Vmuchar_t*)sbrk(0);
+ 		if(addr < (Vmuchar_t*)caddr ) /* in sbrk space */
+ 			return NIL(Void_t*);
+ 		else
++#endif
+ 		{	(void)munmap(caddr, csize);
+ 			return caddr;
+ 		}