Silences

md4.c:286:0: warning: "R1" redefined
 #define R1(a,b,c,d,k,s) a=rol(a+F(b,c,d)+x[k],s);
 ^
In file included from /freetz/freetz-dev/toolchain/build/arm_gcc-5.5.0_uClibc-1.0.14-nptl_kernel-4.4/arm-linux-uclibcgnueabi/include/signal.h:358:0,
                 from ./signal.h:52,
                 from ./sys/select.h:110,
                 from /freetz/freetz-dev/toolchain/build/arm_gcc-5.5.0_uClibc-1.0.14-nptl_kernel-4.4/arm-linux-uclibcgnueabi/include/sys/types.h:219,
                 from ./sys/types.h:39,
                 from ./stdio.h:58,
                 from md4.h:22,
                 from md4.c:24:
/freetz/freetz-dev/toolchain/build/arm_gcc-5.5.0_uClibc-1.0.14-nptl_kernel-4.4/arm-linux-uclibcgnueabi/include/sys/ucontext.h:45:0: note: this is the location of the previous definition
 #define R1 R1
 ^

--- lib/md4.c
+++ lib/md4.c
@@ -201,6 +201,15 @@
 #define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
 #define H(x, y, z) ((x) ^ (y) ^ (z))
 #define rol(x, n) (((x) << (n)) | ((uint32_t) (x) >> (32 - (n))))
+
+/*
+ avoid
+   warning: "R1/R2/R3" redefined
+   include/sys/ucontext.h:L:C: note: this is the location of the previous definition
+*/
+#undef R1
+#undef R2
+#undef R3
 #define R1(a,b,c,d,k,s) a=rol(a+F(b,c,d)+x[k],s);
 #define R2(a,b,c,d,k,s) a=rol(a+G(b,c,d)+x[k]+K1,s);
 #define R3(a,b,c,d,k,s) a=rol(a+H(b,c,d)+x[k]+K2,s);