[Makefile] Prevent gcc from generating trampolines

LibOS/shim/src/Makefile

@@ -6,7 +6,7 @@ include ../../../Pal/src/Makefile.Host
 OMIT_FRAME_POINTER = no
 
 CFLAGS	= -Wall -fPIC -std=c11 -Winline -Wwrite-strings \
-	  -fmerge-all-constants -Wstrict-prototypes \
+	  -fmerge-all-constants -Wstrict-prototypes -Wtrampolines \
 	  -Werror=implicit-function-declaration \
 	  $(cc-option, -Wnull-dereference) \
 	  -fno-stack-protector -fno-builtin -Wno-inline \

Pal/src/host/FreeBSD/Makefile.am

@@ -3,7 +3,7 @@ HOST_DIR = host/$(PAL_HOST)
 
 CFLAGS	= -Wall -fPIC -O2 -std=gnu99 -fgnu89-inline -U_FORTIFY_SOURCE \
 	  -fno-omit-frame-pointer \
-	  -fno-stack-protector -fno-builtin
+	  -fno-stack-protector -fno-builtin -Wtrampolines
 ASFLAGS = -DPIC -DSHARED -fPIC -DASSEMBLER -Wa,--noexecstack \
 	  -x assembler-with-cpp
 LDFLAGS	= -shared -nostdlib -z combreloc -z defs \

Pal/src/host/Linux-SGX/Makefile.am

@@ -3,7 +3,7 @@ HOST_DIR = host/$(PAL_HOST)
 
 CFLAGS	= -Wall -fPIC -O2 -maes -std=c11 -U_FORTIFY_SOURCE \
 	  -fno-omit-frame-pointer \
-	  -fno-stack-protector -fno-builtin
+	  -fno-stack-protector -fno-builtin -Wtrampolines
 
 EXTRAFLAGS = -Wextra $(call cc-option,-Wnull-dereference)
 

Pal/src/host/Linux/Makefile.am

@@ -3,7 +3,7 @@ HOST_DIR = host/$(PAL_HOST)
 SEC_DIR = security/$(PAL_HOST)
 
 CFLAGS	= -Wall -fPIC -O2 -std=c11 -U_FORTIFY_SOURCE \
-	  -fno-stack-protector -fno-builtin
+	  -fno-stack-protector -fno-builtin -Wtrampolines
 
 EXTRAFLAGS = -Wextra $(call cc-option,-Wnull-dereference)