Ports/ncurses: Check for proper tic version during install

MacOS ships with an out of date ncurses that can't properly generate
terminfo from the newer source code. This change checks for a valid
`tic` executable of the proper version, first in PATH and then in
the Homebrew cellar if brew is installed. Otherwise it aborts
installation.

See comment in the code as well as the following for details:
https://github.com/termux/termux-packages/issues/4487#issuecomment-626277493
https://lists.gnu.org/archive/html/bug-ncurses/2019-07/msg00020.html.

Ports/ncurses/package.sh

@@ -15,10 +15,63 @@ configopts=(
 files="https://invisible-mirror.net/archives/ncurses/ncurses-${version}.tar.gz ncurses-${version}.tar.gz 97fc51ac2b085d4cde31ef4d2c3122c21abc217e9090a43a30fc5ec21684e059"
 auth_type="sha256"
 
+check_tic_version() {
+    local tic_path="$1"
+
+    # "ncurses A.B.C" -> "A.B.C" -> "A"
+    local major_version="$($tic_path -V | cut -d ' ' -f2 | cut -d '.' -f1)"
+
+    [ "$major_version" -ge 6 ]
+}
+
+get_tic_path() {
+    # Installation involves generating terminfo files using `tic`.
+    # It seems MacOS ships with an older version of ncurses which has a
+    # `tic` binary that cannot properly parse the `terminfo.src` that ships
+    # with the version we build.
+    # So ensure that at least tic 6.0 is available.
+    # See https://github.com/termux/termux-packages/issues/4487#issuecomment-626277493
+    # and https://lists.gnu.org/archive/html/bug-ncurses/2019-07/msg00020.html.
+
+    if command -v tic >/dev/null; then
+        if check_tic_version "tic"; then
+            echo "tic"
+            return 0
+        else
+            # Check for Homebrew installation.
+            if command -v brew >/dev/null; then
+                local cellar_path=$(brew --cellar ncurses)
+                local highest_version=$(ls "$cellar_path" | head -1)
+                local tic_path="$cellar_path/$highest_version/bin/tic"
+
+                if check_tic_version "$tic_path"; then
+                    echo "$tic_path"
+                    return 0
+                fi
+            fi
+        fi
+    fi
+
+    return 1
+}
+
 pre_configure() {
     export CPPFLAGS="-P"
 }
 
+install() {
+    local tic_path=$(get_tic_path)
+    if [ ! $? ]; then
+        echo "Error: installing cross-compiled ncurses requires locally installed ncurses >= 6.0"
+        exit 1
+    fi
+
+    echo "Using $tic_path from $($tic_path -V)"
+
+    export TIC_PATH="$tic_path"
+    run make DESTDIR=$DESTDIR "${installopts[@]}" install
+}
+
 post_install() {
     # Compatibility symlinks for merged libraries.
     for lib in tinfo tic curses; do