fix build regression in arm asm for memcpy

commit 27828f7e fixed compatibility
with clang's internal assembler, but broke compatibility with gas and
the traditional arm asm syntax by switching to the arm "unified
assembler language" (UAL). recent versions of gas also support UAL,
but require the .syntax directive to be used to switch to it. clang on
the other hand defaults to UAL. and old versions of gas (still
relevant) don't support UAL at all.

for the conditional ldm/stm instructions, "ia" is default and can just
be omitted, resulting in a mnemonic that's compatible with both
traditional and UAL syntax. but for byte/halfword loads and stores,
there seems to be no mnemonic compatible with both, and thus .word is
used to produce the desired opcode explicitly. the .inst directive is
not used because it is not compatible with older assemblers.

src/string/armel/memcpy.s

@@ -73,12 +73,12 @@ memcpy:
          */
         movs	r12, r3, lsl #31
         sub	r2, r2, r3		/* we know that r3 <= r2 because r2 >= 4 */
-        ldrbmi	r3, [r1], #1
-        ldrbcs	r4, [r1], #1
-        ldrbcs	r12,[r1], #1
-        strbmi	r3, [r0], #1
-        strbcs	r4, [r0], #1
-        strbcs	r12,[r0], #1
+        .word 0x44d13001 /* ldrbmi r3, [r1], #1 */
+        .word 0x24d14001 /* ldrbcs r4, [r1], #1 */
+        .word 0x24d1c001 /* ldrbcs r12,[r1], #1 */
+        .word 0x44c03001 /* strbmi r3, [r0], #1 */
+        .word 0x24c04001 /* strbcs r4, [r0], #1 */
+        .word 0x24c0c001 /* strbcs r12,[r0], #1 */
 
 src_aligned:
 
@@ -101,10 +101,10 @@ src_aligned:
 
         /* conditionnaly copies 0 to 7 words (length in r3) */
         movs	r12, r3, lsl #28
-        ldmiacs	r1!, {r4, r5, r6, r7}	/* 16 bytes */
-        ldmiami	r1!, {r8, r9}			/*  8 bytes */
-        stmiacs	r0!, {r4, r5, r6, r7}
-        stmiami	r0!, {r8, r9}
+        ldmcs	r1!, {r4, r5, r6, r7}		/* 16 bytes */
+        ldmmi	r1!, {r8, r9}			/*  8 bytes */
+        stmcs	r0!, {r4, r5, r6, r7}
+        stmmi	r0!, {r8, r9}
         tst    	r3, #0x4
         ldrne	r10,[r1], #4			/*  4 bytes */
         strne	r10,[r0], #4
@@ -171,18 +171,18 @@ less_than_32_left:
 
         /* conditionnaly copies 0 to 31 bytes */
         movs	r12, r2, lsl #28
-        ldmiacs	r1!, {r4, r5, r6, r7}	/* 16 bytes */
-        ldmiami	r1!, {r8, r9}			/*  8 bytes */
-        stmiacs	r0!, {r4, r5, r6, r7}
-        stmiami	r0!, {r8, r9}
+        ldmcs	r1!, {r4, r5, r6, r7}		/* 16 bytes */
+        ldmmi	r1!, {r8, r9}			/*  8 bytes */
+        stmcs	r0!, {r4, r5, r6, r7}
+        stmmi	r0!, {r8, r9}
         movs	r12, r2, lsl #30
         ldrcs	r3, [r1], #4			/*  4 bytes */
-        ldrhmi	r4, [r1], #2			/*  2 bytes */
+        .word 0x40d140b2 /* ldrhmi r4, [r1], #2 */ /*  2 bytes */
         strcs	r3, [r0], #4
-        strhmi	r4, [r0], #2
+        .word 0x40c040b2 /* strhmi r4, [r0], #2 */
         tst    	r2, #0x1
-        ldrbne	r3, [r1]				/*  last byte  */
-        strbne	r3, [r0]
+        .word 0x15d13000 /* ldrbne r3, [r1] */	/*  last byte  */
+        .word 0x15c03000 /* strbne r3, [r0] */
 
         /* we're done! restore everything and return */
 1:	ldmfd	sp!, {r5-r11}
@@ -224,11 +224,11 @@ non_congruent:
          * becomes aligned to 32 bits (r5 = nb of words to copy for alignment)
          */
         movs	r5, r5, lsl #31
-        strbmi	r3, [r0], #1
+        .word 0x44c03001 /* strbmi r3, [r0], #1 */
         movmi	r3, r3, lsr #8
-        strbcs	r3, [r0], #1
+        .word 0x24c03001 /* strbcs r3, [r0], #1 */
         movcs	r3, r3, lsr #8
-        strbcs	r3, [r0], #1
+        .word 0x24c03001 /* strbcs r3, [r0], #1 */
         movcs	r3, r3, lsr #8
 
         cmp	r2, #4
@@ -355,23 +355,23 @@ less_than_thirtytwo:
 partial_word_tail:
 	/* we have a partial word in the input buffer */
 	movs	r5, lr, lsl #(31-3)
-	strbmi	r3, [r0], #1
+	.word 0x44c03001 /* strbmi r3, [r0], #1 */
         movmi	r3, r3, lsr #8
-        strbcs	r3, [r0], #1
+        .word 0x24c03001 /* strbcs r3, [r0], #1 */
         movcs	r3, r3, lsr #8
-        strbcs	r3, [r0], #1
+        .word 0x24c03001 /* strbcs r3, [r0], #1 */
 
         /* Refill spilled registers from the stack. Don't update sp. */
         ldmfd	sp, {r5-r11}
 
 copy_last_3_and_return:
 	movs	r2, r2, lsl #31	/* copy remaining 0, 1, 2 or 3 bytes */
-        ldrbmi	r2, [r1], #1
-        ldrbcs	r3, [r1], #1
-        ldrbcs	r12,[r1]
-        strbmi	r2, [r0], #1
-        strbcs	r3, [r0], #1
-        strbcs	r12,[r0]
+        .word 0x44d12001 /* ldrbmi r2, [r1], #1 */
+        .word 0x24d13001 /* ldrbcs r3, [r1], #1 */
+        .word 0x25d1c000 /* ldrbcs r12,[r1] */
+        .word 0x44c02001 /* strbmi r2, [r0], #1 */
+        .word 0x24c03001 /* strbcs r3, [r0], #1 */
+        .word 0x25c0c000 /* strbcs r12,[r0] */
 
         /* we're done! restore sp and spilled registers and return */
         add    	sp,  sp, #28