sophus: compile on x86-64 arch (resolves #497)

[bulwahn]

This commit implements Christian Ege's suggestion in the meta-ros issue tracker to make gcc only warn on ignored template attributes.

[bulwahn]

I have successfully built core-image-ros-world on these two build configurations:

Build Configuration:
BB_VERSION        = "1.33.4"
BUILD_SYS         = "x86_64-linux"
NATIVELSBSTRING   = "ubuntu-14.04"
TARGET_SYS        = "i586-oe-linux"
MACHINE           = "qemux86"
DISTRO            = "nodistro"
DISTRO_VERSION    = "nodistro.0"
TUNE_FEATURES     = "m32 i586"
TARGET_FPU        = ""
meta              = "master:de7914954571ea8e717f56b6d6df13157b0973bc"
meta-oe           
meta-multimedia   
meta-python       = "master:bd259171ec0c2163a2c1025e1b83ae379cee96a7"
meta-ros          = "resolve-issue-#497:9d6db38f0d38822b2e89af931038f5f4cce9a470"

Build Configuration:
BB_VERSION        = "1.33.4"
BUILD_SYS         = "x86_64-linux"
NATIVELSBSTRING   = "ubuntu-14.04"
TARGET_SYS        = "x86_64-oe-linux"
MACHINE           = "qemux86-64"
DISTRO            = "nodistro"
DISTRO_VERSION    = "nodistro.0"
TUNE_FEATURES     = "m64 core2"
TARGET_FPU        = ""
meta              = "master:de7914954571ea8e717f56b6d6df13157b0973bc"
meta-oe           
meta-multimedia   
meta-python       = "master:bd259171ec0c2163a2c1025e1b83ae379cee96a7"
meta-ros          = "resolve-issue-#497:9d6db38f0d38822b2e89af931038f5f4cce9a470"

[bulwahn]

@rojkov Please review, test and merge. Thanks.

[rojkov]

core-image-ros-world builds successfully for me too with

Build Configuration:
BB_VERSION        = "1.34.0"
BUILD_SYS         = "x86_64-linux"
NATIVELSBSTRING   = "fedora-25"
TARGET_SYS        = "i586-oe-linux"
MACHINE           = "qemux86"
DISTRO            = "nodistro"
DISTRO_VERSION    = "nodistro.0"
TUNE_FEATURES     = "m32 i586"
TARGET_FPU        = ""
meta              = "master:de7914954571ea8e717f56b6d6df13157b0973bc"
meta-oe           
meta-python       
meta-multimedia   = "master:66b88f7729d24ef2e3469fcaca172f420c4d54be"
meta-ros          = "bulwahn-resolve-issue-497-v1:9d6db38f0d38822b2e89af931038f5f4cce9a470"

and

Build Configuration:
BB_VERSION        = "1.34.0"
BUILD_SYS         = "x86_64-linux"
NATIVELSBSTRING   = "fedora-25"
TARGET_SYS        = "x86_64-oe-linux"
MACHINE           = "qemux86-64"
DISTRO            = "nodistro"
DISTRO_VERSION    = "nodistro.0"
TUNE_FEATURES     = "m64 core2"
TARGET_FPU        = ""
meta              = "master:de7914954571ea8e717f56b6d6df13157b0973bc"
meta-oe           
meta-python       
meta-multimedia   = "master:66b88f7729d24ef2e3469fcaca172f420c4d54be"
meta-ros          = "bulwahn-resolve-issue-497-v1:9d6db38f0d38822b2e89af931038f5f4cce9a470"