diff --git a/Makefile b/Makefile
index a40e71c30d..448a22e123 100644
--- a/Makefile
+++ b/Makefile
@@ -136,6 +136,9 @@ all::
 # Define THREADED_DELTA_SEARCH if you have pthreads and wish to exploit
 # parallel delta searching when packing objects.
 #
+# Define NEEDS_QUICK_QSORT if your qsort() implementation has O(n^2)
+# worst case complexity.
+#
 
 GIT-VERSION-FILE: .FORCE-GIT-VERSION-FILE
 	@"$(SHELL_PATH)" ./GIT-VERSION-GEN
@@ -523,6 +526,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	NO_SVN_TESTS = YesPlease
 	NO_PERL_MAKEMAKER = YesPlease
 	NO_R_TO_GCC_LINKER = YesPlease
+	NEEDS_QUICK_QSORT = YesPlease
 	NO_EXTRA_PROGRAMS = YesPlease
 	COMPAT_CFLAGS += -D__USE_MINGW_ACCESS -DNOGDI -Icompat
 	COMPAT_CFLAGS += -DSTRIP_EXTENSION=\".exe\"
@@ -741,6 +745,10 @@ ifdef NO_MEMMEM
 	COMPAT_CFLAGS += -DNO_MEMMEM
 	COMPAT_OBJS += compat/memmem.o
 endif
+ifdef NEEDS_QUICK_QSORT
+	COMPAT_CFLAGS += -DNEEDS_QUICK_QSORT
+	COMPAT_OBJS += compat/qsort.o
+endif
 
 ifdef THREADED_DELTA_SEARCH
 	BASIC_CFLAGS += -DTHREADED_DELTA_SEARCH
diff --git a/compat/qsort.c b/compat/qsort.c
new file mode 100644
index 0000000000..734866e5bc
--- /dev/null
+++ b/compat/qsort.c
@@ -0,0 +1,60 @@
+#include "../git-compat-util.h"
+
+/* This merge sort implementation is simplified from glibc's. */
+static void msort_with_tmp(void *b, size_t n, size_t s,
+			   int (*cmp)(const void *, const void *),
+			   char *t)
+{
+	char *tmp;
+	char *b1, *b2;
+	size_t n1, n2;
+
+	if (n <= 1)
+		return;
+
+	n1 = n / 2;
+	n2 = n - n1;
+	b1 = b;
+	b2 = (char *)b + (n1 * s);
+
+	msort_with_tmp(b1, n1, s, cmp, t);
+	msort_with_tmp(b2, n2, s, cmp, t);
+
+	tmp = t;
+
+	while (n1 > 0 && n2 > 0) {
+		if (cmp(b1, b2) <= 0) {
+			memcpy(tmp, b1, s);
+			tmp += s;
+			b1 += s;
+			--n1;
+		} else {
+			memcpy(tmp, b2, s);
+			tmp += s;
+			b2 += s;
+			--n2;
+		}
+	}
+	if (n1 > 0)
+		memcpy(tmp, b1, n1 * s);
+	memcpy(b, t, (n - n2) * s);
+}
+
+void git_qsort(void *b, size_t n, size_t s,
+	       int (*cmp)(const void *, const void *))
+{
+	const size_t size = n * s;
+
+	if (size < 1024) {
+		char buf[size]; /* gcc-ism */
+
+		/* The temporary array is small, so put it on
+		   the stack.  */
+		msort_with_tmp(b, n, s, cmp, buf);
+	} else {
+		/* It's somewhat large, so malloc it.  */
+		char *tmp = malloc(size);
+		msort_with_tmp(b, n, s, cmp, tmp);
+		free(tmp);
+	}
+}
diff --git a/git-compat-util.h b/git-compat-util.h
index 5a81bc9e76..0f92d1d570 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -645,4 +645,10 @@ extern __attribute__((noreturn)) int git_exit(int code);
 
 #endif /* __MINGW32__ */
 
+#ifdef NEEDS_QUICK_QSORT
+void git_qsort(void *base, size_t nmemb, size_t size,
+	       int(*compar)(const void *, const void *));
+#define qsort git_qsort
+#endif
+
 #endif