Revert "Build: Include headers from LibC, LibM, and LibPthread with -isystem"

This reverts commit c1eb744ff0.

Libraries/LibC/CMakeLists.txt

@@ -52,8 +52,6 @@ file(GLOB ELF_SOURCES "../LibELF/*.cpp")
 set(ELF_SOURCES ${ELF_SOURCES} ../LibELF/Arch/i386/plt_trampoline.S)
 
 add_library(crt0 STATIC crt0.cpp)
-# We need include headers from LibC in crt0. namely, <assert.h>
-target_include_directories(crt0 PRIVATE ${CMAKE_CURRENT_SOURCE_DIR})
 add_custom_command(
     TARGET crt0
     COMMAND install -D $<TARGET_OBJECTS:crt0> ${CMAKE_INSTALL_PREFIX}/usr/lib/crt0.o

Libraries/LibDebug/DebugSession.h

@@ -33,11 +33,11 @@
 #include <AK/Optional.h>
 #include <AK/OwnPtr.h>
 #include <AK/String.h>
+#include <LibC/sys/arch/i386/regs.h>
 #include <LibDebug/DebugInfo.h>
 #include <LibELF/Loader.h>
 #include <signal.h>
 #include <stdio.h>
-#include <sys/arch/i386/regs.h>
 #include <sys/ptrace.h>
 #include <sys/wait.h>
 #include <unistd.h>

Libraries/LibM/CMakeLists.txt

@@ -3,4 +3,5 @@ set(SOURCES
 )
 
 serenity_libc(LibM m)
+target_include_directories(LibM PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(LibM LibC)

Libraries/LibM/math.cpp

@@ -24,8 +24,8 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <assert.h>
-#include <math.h>
+#include <LibC/assert.h>
+#include <LibM/math.h>
 #include <stdint.h>
 #include <stdlib.h>
 

Libraries/LibPthread/CMakeLists.txt

@@ -4,3 +4,4 @@ set(SOURCES
 
 serenity_libc(LibPthread pthread)
 target_link_libraries(LibPthread LibC)
+target_include_directories(LibPthread PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})