diff --git a/SheepShaver/src/Unix/Linux/asm_linux.S b/SheepShaver/src/Unix/Linux/asm_linux.S
index 79d698e5..d5362cf1 100644
--- a/SheepShaver/src/Unix/Linux/asm_linux.S
+++ b/SheepShaver/src/Unix/Linux/asm_linux.S
@@ -566,19 +566,19 @@ C_SYMBOL_NAME(execute_68k):
  *  uint32 call_macos1(uint32 tvect{r3}, uint32 arg1{r4}) ... - Call MacOS routines
  */
 
-.macro	prolog
+ASM_MACRO_START	prolog
 	mflr	r0
 	stw	r0,4(r1)
 	stwu	r1,-64(r1)
-.endm
+ASM_MACRO_END
 
-.macro	epilog
+ASM_MACRO_START	epilog
 	lwz	r13,XLM_TOC(0)
 	lwz	r0,64+4(r1)
 	mtlr	r0
 	addi	r1,r1,64
 	blr
-.endm
+ASM_MACRO_END
 
 	ASM_GLOBAL_DIRECTIVE C_SYMBOL_NAME(call_macos)
 C_SYMBOL_NAME(call_macos):
diff --git a/SheepShaver/src/Unix/main_unix.cpp b/SheepShaver/src/Unix/main_unix.cpp
index 8e69e3b4..4f15d6c4 100644
--- a/SheepShaver/src/Unix/main_unix.cpp
+++ b/SheepShaver/src/Unix/main_unix.cpp
@@ -165,6 +165,9 @@ struct sigregs {
 };
 
 #if defined(__linux__)
+#include <sys/ucontext.h>
+#define MACHINE_REGISTERS(scp)	((machine_regs *)(((ucontext_t *)scp)->uc_mcontext.regs))
+
 struct machine_regs : public pt_regs
 {
 	u_long & cr()				{ return pt_regs::ccr; }
@@ -179,12 +182,15 @@ struct machine_regs : public pt_regs
 	u_long & gpr(int i)			{ return pt_regs::gpr[i]; }
 	uint32 gpr(int i) const		{ return pt_regs::gpr[i]; }
 };
-
-#include <sys/ucontext.h>
-#define MACHINE_REGISTERS(scp)	((machine_regs *)(((ucontext_t *)scp)->uc_mcontext.regs))
 #endif
 
 #if defined(__APPLE__) && defined(__MACH__)
+#include <sys/signal.h>
+extern "C" int sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss);
+
+#include <sys/ucontext.h>
+#define MACHINE_REGISTERS(scp)	((machine_regs *)(((ucontext_t *)scp)->uc_mcontext))
+
 struct machine_regs : public mcontext
 {
 	uint32 & cr()				{ return ss.cr; }
@@ -199,12 +205,6 @@ struct machine_regs : public mcontext
 	uint32 & gpr(int i)			{ return (&ss.r0)[i]; }
 	uint32 gpr(int i) const		{ return (&ss.r0)[i]; }
 };
-
-#include <sys/ucontext.h>
-#define MACHINE_REGISTERS(scp)	((machine_regs *)(((ucontext_t *)scp)->uc_mcontext))
-
-#include <sys/signal.h>
-extern "C" int sigaltstack(const struct sigaltstack *ss, struct sigaltstack *oss);
 #endif
 
 static void build_sigregs(sigregs *srp, machine_regs *mrp)
diff --git a/SheepShaver/src/Unix/ppc_asm.tmpl b/SheepShaver/src/Unix/ppc_asm.tmpl
index 59653a0c..08473ccb 100644
--- a/SheepShaver/src/Unix/ppc_asm.tmpl
+++ b/SheepShaver/src/Unix/ppc_asm.tmpl
@@ -1,11 +1,20 @@
 #if (defined(__APPLE__) && defined(__MACH__))
-#define C_SYMBOL_NAME(X) _ ## X
+#define C_SYMBOL_NAME(NAME)	_ ## NAME
+#define ASM_MACRO_END		.endmacro
+#endif
+
+/* Defaults for GNU assembler */
+#ifndef ASM_MACRO_START
+#define ASM_MACRO_START		.macro
+#endif
+#ifndef ASM_MACRO_END
+#define ASM_MACRO_END		.endm
 #endif
 #ifndef C_SYMBOL_NAME
-#define C_SYMBOL_NAME(X) X
+#define C_SYMBOL_NAME(NAME)	NAME
 #endif
 #ifndef ASM_GLOBAL_DIRECTIVE
-#define ASM_GLOBAL_DIRECTIVE .globl
+#define ASM_GLOBAL_DIRECTIVE	.globl
 #endif
 
 /* Register names */