vbam: various !x86 fixes:

- limit the use of an asm optimisation for `std::sqrt()' to x86 archs,
since it breaks the build everywhere else.
- remove `-fopenmp' for base-gcc archs; it breaks the build on them
- remove `-Wno-c++11-narrowing' from CXXFLAGS; no occurrence of it has
been found, and such warning is notably useful for arm* and powerpc.
Tested on sparc64 (kmos@), macppc and amd64 (me).

OK kmos@

emulators/vbam/Makefile

@@ -1,4 +1,4 @@
-# $OpenBSD: Makefile,v 1.33 2019/11/11 11:13:13 fcambus Exp $
+# $OpenBSD: Makefile,v 1.34 2019/11/17 00:14:36 cwen Exp $
 
 BROKEN-alpha =		ICE or OOM on hq_implementation.cpp
 BROKEN-hppa =		ICE or OOM on src/filters/hq/c/hq_base.h:421
@@ -42,7 +42,7 @@ CONFIGURE_ARGS +=	-DENABLE_LTO=OFF
 # -DCMAKE_ASM_NASM_COMPILER=yasm, but then linking fails.
 CONFIGURE_ARGS +=	-DENABLE_ASM=OFF
 
-CXXFLAGS +=		-Wno-c++11-narrowing -I${X11BASE}/include
+CXXFLAGS +=		-I${X11BASE}/include
 
 NO_TEST =		Yes
 

emulators/vbam/patches/patch-CMakeLists_txt

@@ -0,0 +1,16 @@
+$OpenBSD: patch-CMakeLists_txt,v 1.3 2019/11/17 00:14:36 cwen Exp $
+
+Fix build with ports-gcc:
+eg++: error: libgomp.spec: No such file or directory
+
+Index: CMakeLists.txt
+--- CMakeLists.txt.orig
++++ CMakeLists.txt
+@@ -526,7 +526,6 @@ if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID S
+             endif()
+         endif()
+ 
+-        set(MY_C_FLAGS ${MY_C_FLAGS} -fopenmp)
+     endif()
+ 
+     if(CMAKE_CXX_COMPILER_ID STREQUAL GNU)

emulators/vbam/patches/patch-src_filters_xBRZ_xbrz_cpp

@@ -0,0 +1,16 @@
+$OpenBSD: patch-src_filters_xBRZ_xbrz_cpp,v 1.1 2019/11/17 00:14:36 cwen Exp $
+
+Fix "error: impossible constraint in 'asm'" on !x86
+
+Index: src/filters/xBRZ/xbrz.cpp
+--- src/filters/xBRZ/xbrz.cpp.orig
++++ src/filters/xBRZ/xbrz.cpp
+@@ -66,7 +66,7 @@ uint32_t gradientARGB(uint32_t pixFront, uint32_t pixB
+ 
+ inline double fastSqrt(double n)
+ {
+-#ifdef __GNUC__ || __clang__ || __MINGW64_VERSION_MAJOR || __MINGW32_MAJOR_VERSION
++#if defined(__x86_64__) || defined(__i386__)
+     __asm__ ("fsqrt" : "+t" (n));
+     return n;
+ #elif _MSC_VER && _M_IX86