Export of internal Abseil changes.

--
fe689b30f9a3a614e8a577997cc340043d01c2f1 by Abseil Team <absl-team@google.com>:

Change arm32 linux backtrace to use the generic implementation.

PiperOrigin-RevId: 218386158

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86f8678d055d32edc989e6a4d1dc49c3a15cd350 by Abseil Team <absl-team@google.com>:

Update documentation on SHARED_LOCKS_REQUIRED and EXCLUSIVE_LOCKS_REQUIRED so that users know the differences between them.

PiperOrigin-RevId: 218365545

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22947b48ce4a1ba71ad4794f762235dac3a1df12 by Greg Falcon <gfalcon@google.com>:

The from_chars implementation incorrectly assumed `uint32_t` was `unsigned int`.

`strings_internal::BigUnsigned` had `uint32_t` and `uint64_t` constructors; when both of these types differ from `unsigned int`, `BigUnsigned(1u)` is ambiguous (neither conversion is better).

Fix this by removing the `uint32_t` constructor.  When the `uint64_t` constructor is called with a literal or type that is 32 bits or narrower, the compiler is smart enough to optimize away the two-word case, so this fix is free.

PiperOrigin-RevId: 218346935

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7201ab430bb90ca0e30b102915d02564f61353eb by Abseil Team <absl-team@google.com>:

Fix formatting errors discovered during merge conflict.

PiperOrigin-RevId: 218229891
GitOrigin-RevId: fe689b30f9a3a614e8a577997cc340043d01c2f1
Change-Id: I5d382482ad227d48ffe57b243ce11b1eb44a1314

1 files changed, 12 insertions, 6 deletions

diff --git a/CMake/AbseilHelpers.cmake b/CMake/AbseilHelpers.cmake
index 94d10778b0eb..96813b083d01 100644
--- a/CMake/AbseilHelpers.cmake
+++ b/CMake/AbseilHelpers.cmake
@@ -112,26 +112,30 @@ endfunction()
 # User can then use the library as absl::main_lib (although absl_main_lib is defined too).
 #
 # TODO: Implement "ALWAYSLINK"
- function(absl_cc_library)
+
+function(absl_cc_library)
   cmake_parse_arguments(ABSL_CC_LIB
     "DISABLE_INSTALL;PUBLIC;TESTONLY"
     "NAME"
     "HDRS;SRCS;COPTS;DEFINES;LINKOPTS;DEPS"
     ${ARGN}
   )
-   if (NOT ABSL_CC_LIB_TESTONLY OR ABSL_RUN_TESTS)
+
+  if (NOT ABSL_CC_LIB_TESTONLY OR ABSL_RUN_TESTS)
     if (ABSL_CC_LIB_PUBLIC)
       set(_NAME "absl_${ABSL_CC_LIB_NAME}")
     else()
       set(_NAME "absl_internal_${ABSL_CC_LIB_NAME}")
     endif()
-     # Check if this is a header-only library
+
+    # Check if this is a header-only library
     if ("${ABSL_CC_LIB_SRCS}" STREQUAL "")
       set(ABSL_CC_LIB_IS_INTERFACE 1)
     else()
       set(ABSL_CC_LIB_IS_INTERFACE 0)
     endif()
-     if(NOT ABSL_CC_LIB_IS_INTERFACE)
+
+    if(NOT ABSL_CC_LIB_IS_INTERFACE)
       add_library(${_NAME} STATIC "")
       target_sources(${_NAME} PRIVATE ${ABSL_CC_LIB_SRCS} ${ABSL_CC_LIB_HDRS})
       target_include_directories(${_NAME}
@@ -144,7 +148,8 @@ endfunction()
         PRIVATE ${ABSL_CC_LIB_LINKOPTS}
       )
       target_compile_definitions(${_NAME} PUBLIC ${ABSL_CC_LIB_DEFINES})
-       # Add all Abseil targets to a a folder in the IDE for organization.
+
+      # Add all Abseil targets to a a folder in the IDE for organization.
       set_property(TARGET ${_NAME} PROPERTY FOLDER ${ABSL_IDE_FOLDER})
     else()
       # Generating header-only library
@@ -155,7 +160,8 @@ endfunction()
       )
       target_compile_definitions(${_NAME} INTERFACE ${ABSL_CC_LIB_DEFINES})
     endif()
-     if(ABSL_CC_LIB_PUBLIC)
+
+    if(ABSL_CC_LIB_PUBLIC)
       add_library(absl::${ABSL_CC_LIB_NAME} ALIAS ${_NAME})
     endif()
   endif()