Allow LINK_SEARCH_{START,END}_STATIC props to have default values.

Use the CMAKE_LINK_SEARCH_START_STATIC and CMAKE_LINK_SEARCH_END_STATIC
variables to initialize the LINK_SEARCH_START_STATIC and
LINK_SEARCH_END_STATIC target properties respectively.

Help/manual/cmake-variables.7.rst

@@ -47,6 +47,8 @@ Variables that Provide Information
    /variable/CMAKE_JOB_POOL_COMPILE
    /variable/CMAKE_JOB_POOL_LINK
    /variable/CMAKE_LINK_LIBRARY_SUFFIX
+   /variable/CMAKE_LINK_SEARCH_END_STATIC
+   /variable/CMAKE_LINK_SEARCH_START_STATIC
    /variable/CMAKE_MAJOR_VERSION
    /variable/CMAKE_MAKE_PROGRAM
    /variable/CMAKE_MATCH_COUNT

Help/prop_tgt/LINK_SEARCH_END_STATIC.rst

@@ -10,5 +10,9 @@ paths are not known or (in some cases) are in implicit link
 directories for the platform.  By default CMake adds an option at the
 end of the library list (if necessary) to set the linker search type
 back to its starting type.  This property switches the final linker
-search type to -Bstatic regardless of how it started.  See also
-LINK_SEARCH_START_STATIC.
+search type to -Bstatic regardless of how it started.
+
+This property is initialized by the value of the variable
+CMAKE_LINK_SEARCH_END_STATIC if it is set when a target is created.
+
+See also LINK_SEARCH_START_STATIC.

Help/prop_tgt/LINK_SEARCH_START_STATIC.rst

@@ -11,4 +11,9 @@ directories for the platform.  By default the linker search type is
 assumed to be -Bdynamic at the beginning of the library list.  This
 property switches the assumption to -Bstatic.  It is intended for use
 when linking an executable statically (e.g.  with the GNU -static
-option).  See also LINK_SEARCH_END_STATIC.
+option).
+
+This property is initialized by the value of the variable
+CMAKE_LINK_SEARCH_START_STATIC if it is set when a target is created.
+
+See also LINK_SEARCH_END_STATIC.

Help/variable/CMAKE_LINK_SEARCH_END_STATIC.rst

@@ -0,0 +1,18 @@
+CMAKE_LINK_SEARCH_END_STATIC
+----------------------------
+
+End a link line such that static system libraries are used.
+
+Some linkers support switches such as -Bstatic and -Bdynamic to
+determine whether to use static or shared libraries for -lXXX options.
+CMake uses these options to set the link type for libraries whose full
+paths are not known or (in some cases) are in implicit link
+directories for the platform.  By default CMake adds an option at the
+end of the library list (if necessary) to set the linker search type
+back to its starting type.  This property switches the final linker
+search type to -Bstatic regardless of how it started.
+
+This variable is used to initialize the target property
+LINK_SEARCH_END_STATIC for all targets.
+
+See also CMAKE_LINK_SEARCH_START_STATIC.

Help/variable/CMAKE_LINK_SEARCH_START_STATIC.rst

@@ -0,0 +1,19 @@
+CMAKE_LINK_SEARCH_START_STATIC
+------------------------------
+
+Assume the linker looks for static libraries by default.
+
+Some linkers support switches such as -Bstatic and -Bdynamic to
+determine whether to use static or shared libraries for -lXXX options.
+CMake uses these options to set the link type for libraries whose full
+paths are not known or (in some cases) are in implicit link
+directories for the platform.  By default the linker search type is
+assumed to be -Bdynamic at the beginning of the library list.  This
+property switches the assumption to -Bstatic.  It is intended for use
+when linking an executable statically (e.g.  with the GNU -static
+option).
+
+This variable is used to initialize the target property
+LINK_SEARCH_START_STATIC for all targets.
+
+See also CMAKE_LINK_SEARCH_END_STATIC.

Source/cmComputeLinkInformation.cxx

@@ -522,9 +522,10 @@ bool cmComputeLinkInformation::Compute()
   // libraries are found.
   const char* lss =
       this->Target->Target->GetProperty("LINK_SEARCH_END_STATIC");
-  if(cmSystemTools::IsOn(lss))
+  if(lss)
     {
-    this->SetCurrentLinkType(LinkStatic);
+    this->SetCurrentLinkType(
+      cmSystemTools::IsOn(lss) ? LinkStatic : LinkShared);
     }
   else
     {
@@ -862,7 +863,8 @@ void cmComputeLinkInformation::ComputeLinkTypeInfo()
   const char* lss =
       this->Target->Target->GetProperty("LINK_SEARCH_START_STATIC");
   this->StartLinkType = cmSystemTools::IsOn(lss)? LinkStatic : LinkShared;
-  this->CurrentLinkType = this->StartLinkType;
+  this->CurrentLinkType = LinkUnknown;
+  this->SetCurrentLinkType(this->StartLinkType);
 }
 
 //----------------------------------------------------------------------------

Source/cmTarget.cxx

@@ -306,6 +306,8 @@ void cmTarget::SetMakefile(cmMakefile* mf)
     this->SetPropertyDefault("CXX_STANDARD", 0);
     this->SetPropertyDefault("CXX_STANDARD_REQUIRED", 0);
     this->SetPropertyDefault("CXX_EXTENSIONS", 0);
+    this->SetPropertyDefault("LINK_SEARCH_START_STATIC", 0);
+    this->SetPropertyDefault("LINK_SEARCH_END_STATIC", 0);
     }
 
   // Collect the set of configuration types.

Tests/RunCMake/set_property/LINK_SEARCH_STATIC.cmake

@@ -0,0 +1,73 @@
+project(LinkSearchStatic)
+
+set(CMAKE_LINK_SEARCH_START_STATIC ON)
+add_executable(LinkSearchStartStaticInit1 LinkStatic.c)
+get_target_property(LSSS LinkSearchStartStaticInit1
+  LINK_SEARCH_START_STATIC)
+if(NOT LSSS)
+  message(FATAL_ERROR "Failed to correctly initialize LINK_SEARCH_START_STATIC")
+endif()
+unset(CMAKE_LINK_SEARCH_START_STATIC)
+
+add_executable(LinkSearchStartStaticSet1 LinkStatic.c)
+set_target_properties(LinkSearchStartStaticSet1 PROPERTIES
+  LINK_SEARCH_START_STATIC ON)
+get_target_property(LSSS LinkSearchStartStaticSet1
+  LINK_SEARCH_START_STATIC)
+if(NOT LSSS)
+  message(FATAL_ERROR "Failed to correctly set LINK_SEARCH_START_STATIC")
+endif()
+
+set(CMAKE_LINK_SEARCH_START_STATIC OFF)
+add_executable(LinkSearchStartStaticInit2 LinkStatic.c)
+get_target_property(LSSS LinkSearchStartStaticInit2
+  LINK_SEARCH_START_STATIC)
+if(LSSS)
+  message(FATAL_ERROR "Failed to correctly initialize LINK_SEARCH_START_STATIC")
+endif()
+unset(CMAKE_LINK_SEARCH_START_STATIC)
+
+add_executable(LinkSearchStartStaticSet2 LinkStatic.c)
+set_target_properties(LinkSearchStartStaticSet2 PROPERTIES
+  LINK_SEARCH_START_STATIC OFF)
+get_target_property(LSSS LinkSearchStartStaticSet2
+  LINK_SEARCH_START_STATIC)
+if(LSSS)
+  message(FATAL_ERROR "Failed to correctly set LINK_SEARCH_START_STATIC")
+endif()
+
+set(CMAKE_LINK_SEARCH_END_STATIC ON)
+add_executable(LinkSearchEndStaticInit1 LinkStatic.c)
+get_target_property(LSES LinkSearchEndStaticInit1
+  LINK_SEARCH_END_STATIC)
+if(NOT LSES)
+  message(FATAL_ERROR "Failed to correctly initialize LINK_SEARCH_END_STATIC")
+endif()
+unset(CMAKE_LINK_SEARCH_END_STATIC)
+
+add_executable(LinkSearchEndStaticSet1 LinkStatic.c)
+set_target_properties(LinkSearchEndStaticSet1 PROPERTIES
+  LINK_SEARCH_END_STATIC ON)
+get_target_property(LSSS LinkSearchEndStaticSet1
+  LINK_SEARCH_END_STATIC)
+if(NOT LSSS)
+  message(FATAL_ERROR "Failed to correctly set LINK_SEARCH_END_STATIC")
+endif()
+
+set(CMAKE_LINK_SEARCH_END_STATIC OFF)
+add_executable(LinkSearchEndStaticInit2 LinkStatic.c)
+get_target_property(LSES LinkSearchEndStaticInit2
+  LINK_SEARCH_END_STATIC)
+if(LSES)
+  message(FATAL_ERROR "Failed to correctly initialize LINK_SEARCH_END_STATIC")
+endif()
+unset(CMAKE_LINK_SEARCH_END_STATIC)
+
+add_executable(LinkSearchEndStaticSet2 LinkStatic.c)
+set_target_properties(LinkSearchEndStaticSet2 PROPERTIES
+  LINK_SEARCH_END_STATIC ON)
+get_target_property(LSSS LinkSearchEndStaticSet2
+  LINK_SEARCH_END_STATIC)
+if(NOT LSSS)
+  message(FATAL_ERROR "Failed to correctly set LINK_SEARCH_END_STATIC")
+endif()

Tests/RunCMake/set_property/LinkStatic.c

@@ -0,0 +1,5 @@
+#include <math.h>
+int main(void)
+{
+  return (int)sin(0);
+}

Tests/RunCMake/set_property/RunCMakeTest.cmake

@@ -1,3 +1,4 @@
 include(RunCMake)
 
 run_cmake(LINK_LIBRARIES)
+run_cmake(LINK_SEARCH_STATIC)