[lldb] Add terminfo dependency for ncurses support (llvm#126810)

For some operating systems (e.g. chromiumos), terminfo is a separate
package and library from ncurses. Both are still requirements for curses
support in lldb, individually.
    
This is a rework of this original spack commit:

spack/spack@9ea2612

Instead though, this PR uses CMake to detect whether the symbol is
present and defined in the curses library, and only falls back to a separate
tinfo if not found.
    
Without this fix, LLDB cannot be built on these systems.
    
Fixes llvm#101368

Author: ajordanr-google

lldb/cmake/modules/FindCursesAndPanel.cmake

@@ -2,23 +2,55 @@
 # FindCursesAndPanel
 # -----------
 #
-# Find the curses and panel library as a whole.
+# Find the curses, terminfo, and panel library as a whole.
 
-if(CURSES_INCLUDE_DIRS AND CURSES_LIBRARIES AND PANEL_LIBRARIES)
+include(CMakePushCheckState)
+
+function(lldb_check_curses_tinfo CURSES_LIBRARIES CURSES_HAS_TINFO)
+  cmake_reset_check_state()
+  set(CMAKE_REQUIRED_LIBRARIES "${CURSES_LIBRARIES}")
+  # acs_map is one of many symbols that are part of tinfo but could
+  # be bundled in curses.
+  check_symbol_exists(acs_map "curses.h" CURSES_HAS_TINFO)
+endfunction()
+
+if(CURSES_INCLUDE_DIRS AND CURSES_LIBRARIES AND TINFO_LIBRARIES AND PANEL_LIBRARIES)
   set(CURSESANDPANEL_FOUND TRUE)
 else()
   find_package(Curses QUIET)
   find_library(PANEL_LIBRARIES NAMES panel DOC "The curses panel library" QUIET)
   include(FindPackageHandleStandardArgs)
+
+  if(CURSES_FOUND AND PANEL_LIBRARIES)
+    # Sometimes the curses libraries define their own terminfo symbols,
+    # other times they're extern and are defined by a separate terminfo library.
+    # Auto-detect which.
+    lldb_check_curses_tinfo("${CURSES_LIBRARIES}" CURSES_HAS_TINFO)
+    if (NOT CURSES_HAS_TINFO)
+      message(STATUS "curses library missing terminfo symbols, looking for tinfo separately")
+      find_library(TINFO_LIBRARIES NAMES tinfo DOC "The curses tinfo library" QUIET)
+      list(APPEND CURSES_LIBRARIES "${TINFO_LIBRARIES}")
+    endif()
+    set(HAS_TERMINFO_SYMBOLS "$<OR:$<BOOL:${TERMINFO_LIBRARIES}>,$<BOOL:${CURSES_HAS_TINFO}>>")
+  endif()
+
   find_package_handle_standard_args(CursesAndPanel
                                     FOUND_VAR
                                       CURSESANDPANEL_FOUND
                                     REQUIRED_VARS
                                       CURSES_INCLUDE_DIRS
                                       CURSES_LIBRARIES
-                                      PANEL_LIBRARIES)
-  if(CURSES_FOUND AND PANEL_LIBRARIES)
-    mark_as_advanced(CURSES_INCLUDE_DIRS CURSES_LIBRARIES PANEL_LIBRARIES)
+                                      PANEL_LIBRARIES
+                                      HAS_TERMINFO_SYMBOLS)
+
+  if(CURSES_FOUND AND PANEL_LIBRARIES AND HAS_TERMINFO_SYMBOLS)
+    mark_as_advanced(CURSES_INCLUDE_DIRS
+                      PANEL_LIBRARIES
+                      HAS_TERMINFO_SYMBOLS
+                      CURSES_HAS_TINFO)
+  endif()
+  if(TINFO_LIBRARIES)
+    mark_as_advanced(TINFO_LIBRARIES)
   endif()
 endif()