9f99ec21e5
The BR2_ARCH_HAS_ATOMICS was added because on ARC, atomic instructions may not be provided by the architecture and therefore the compiler does not provide the __sync_*() built-ins. However, since then, icu was changed and is now able to use C++11 atomics, or even no atomic operations at all. In fact, icu will: * If possible, it will use C++11 atomics, which internally rely on the __atomic built-ins. These are available since gcc 4.7, and all architectures provide it. On some architectures, you *must* link with libatomic, on some other architectures, they are available built-in, but in all cases, linking against libatomic does not harm. Thanks to this, even ARC with no atomic support (which was the original reason for adding the BR2_ARCH_HAS_ATOMICS) dependency builds fine, provided -latomic is added to LIBS. * If C++11 atomics are not available, then it falls back to __sync_*() built-ins, which allows compilers older than 4.7 to be supported. * If really no atomic mechanism is available, then it falls back to a basic implementation based on a mutex. Conclusion: - The BR2_ARCH_HAS_ATOMICS dependency is no longer needed. - We need to link with -latomic when gcc >= 4.7 is used. Note that reverse dependencies of icu are also changed accordingly. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
32 lines
921 B
Plaintext
32 lines
921 B
Plaintext
config BR2_PACKAGE_ICU
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bool "icu"
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depends on BR2_INSTALL_LIBSTDCPP
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depends on BR2_USE_WCHAR
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depends on BR2_TOOLCHAIN_HAS_THREADS
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# icu does some funky things by generating by itself an ELF
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# file, and it cannot easily be changed to generate FLAT
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# format.
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depends on !BR2_BINFMT_FLAT
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help
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International Components for Unicode.
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http://site.icu-project.org/
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if BR2_PACKAGE_ICU
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config BR2_PACKAGE_ICU_CUSTOM_DATA_PATH
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string "Path to custom data library file"
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help
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This option allows to define the path to a custom data
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library generated with http://apps.icu-project.org/datacustom/
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Make sure you select the appropiate version to match the one
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provided by buildroot.
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Leave empty to not use this functionality.
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endif
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comment "icu needs a toolchain w/ C++, wchar, threads"
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depends on !BR2_BINFMT_FLAT
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depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR || \
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!BR2_TOOLCHAIN_HAS_THREADS
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